[ February 1, 2015 ]
Exploring nine- and pandigitals expressible as sums of two squares
B.S. Rangaswamy (email)
B.S. Rangaswamy enclosed me 2_tier constituents of powers for ninedigitals and pandigitals.
Some have double, triple, quadruple, quintuple and even a sevenfold set of constituents.
He used clever Excel table programming to get some selected (restricted) results
where one of the two powers is an eight-digit number in the case of ninedigitals
and a nine-digit number in the case of pandigitals (the 2nd powers are only resultants).
The filtering and sorting was speeded up with the help of his grandson Puneeth
and daughter in law Indira Ramesh.
Alas, I cannot reproduce the programs in HTML, so I will stick to
displaying partly results and some magical curios for some chosen categories
but without the restrictions imposed by B.S. Rangaswamy.
Interested and involving readers may try to discover existence of other
strange constituents for any of the remaining vast number of nine- and/or pandigitals.
Ninedigital highlights
Here are already some curios (multi solutions per ninedigital allowed)
143625897 = 98762 + 67892 Note the reversals !
143752968 = 84782 + 84782 Twice the same term !
145897362 = 85412 + 85412 Here also twice the same term !
162973458 = 90272 + 90272 And again twice the same term !
143689725 = 88502 + 80852 Both terms are anagrams of each other !
145973682 = 98612 + 69812 Bis - both terms are anagrams of each other !
149683725 = 87542 + 85472 Ter - both terms are anagrams of each other !
Statistical information and more curios are to be found
in one of my dedicated ninedigits pages. Please visit also Statistics and curios
You noticed already that all values A and B are multiples of 3. How come ?
This due to the fact that every ninedigital is divisible by 9 (all digits sums to 45).
In order to be able to separate the 9-factor from the sum of squares, each
value A and B must be a multiple of 3. Idem dito for the pandigitals.
N = A2 + B2
9 * N' = 9 * ( A'2 + B'2 )
9 * N' = ( 9 * A'2 ) + ( 9 * B'2 )
9 * N' = ( 3 * A' )2 + ( 3 * B' )2
Case N.1 ninedigital = strictly single solutions for A2 + B2
A and B restricted to 4-digit numbers
123456978 = 52232 + 98072
[ Smallest ]
123458976 = 74762 + 82202
Many more solutions exist
[ Solutions must be < 200000000 ]
193675842 = 97292 + 99512
194265378 = 97472 + 99632
[ Largest ]
A and B restricted to 5-digit numbers
213576498 = 101372 + 105272
312457986 = 120692 + 129152
412536978 = 127472 + 158132
512374986 = 138152 + 179312
612345978 = 108032 + 222632
712345896 = 142142 + 225902
812356794 = 193652 + 209132
912346857 = 131012 + 272162
[ A selection of solutions ]
Case N.2 ninedigital = strictly double solutions for A2 + B2
A and B restricted to 4-digit numbers
Solutions must be < 200000000.
123475986 = 68252 + 87692 = 69692 + 86552
152367489 = 95672 + 78002 = 95402 + 78332
[ Many more solutions exist ]
A and B restricted to 5-digit numbers
245193768 = 100382 + 120182 = 108422 + 112982
312685749 = 106952 + 140822 = 113102 + 135932
412365978 = 111332 + 169832 = 140132 + 146972
512387493 = 136862 + 180302 = 145862 + 173102
[ Many more solutions exist ]
Case N.3 ninedigital = strictly triple solutions for A2 + B2 Note that these triples are sparingly scattered.
Case N.5 ninedigital = quintuple solutions for A2 + B2
A and B restricted to 4-digit numbers
There exist no strictly quintuple solutions for A2 + B2
The next best thing is to search for them as a subset in higher x-fold solutions,
as for instance in the following 12-fold example from B.S. Rangaswamy.
Case N.7 ninedigital = sevenfold solutions for A2 + B2
A and B restricted to 4-digit numbers
There exist no strictly 7-fold solutions for A2 + B2
The next best thing is to search for them as a subset in higher x-fold solutions,
as for instance in the following 24-fold example from B.S.Rangaswamy.
139876425 = 98762 + 65072
= 96992 + 67682
= 96122 + 68912
= 92132 + 74162
= 90452 + 76202
= 90122 + 76592
= 84452 + 82802
[ 17 more when unrestricted ]
But the first occurence happens within the following 16-fold ninedigital
124879365 = 54392 + 97622
[ smallest ]
= 56492 + 96422
= 60542 + 93932
= 63422 + 92012
= 65462 + 90572
= 71672 + 85742
= 73772 + 83942
[ nine more when unrestricted ]
A and B restricted to 5-digit numbers
There exist no strictly 7-fold solutions for A2 + B2
The next best thing is to search for them as a subset in higher x-fold solutions,
as for instance in the following 8-fold example.
Other subset eightfold solutions are
463879125, 647193825, 691847325, 719348625, 761438925, 763849125,
789346125, 794386125, 794631825, 817639425, 817693425, 821749365,
831249765, 846731925, 879461325, 879463125, 971382465 and 982715634
Case N.9 ninedigital = higher-fold solutions for A2 + B2
A and B restricted to 5-digit numbers
9-fold solutions
728931645 subset from a 16-fold
734189625 subset from a 16-fold
739241685 subset from a 16-fold
837612945 subset from a 16-fold
873469125 subset from a 16-fold
893127645 subset from a 16-fold
897134625 subset from a 16-fold
912634785 subset from a 16-fold
914273685 subset from a 16-fold
948376125 subset from a 16-fold
963417285 subset from a 16-fold
971436258 subset from a 16-fold
981342765 subset from a 16-fold
10-fold solutions
417938625 subset from a 24-fold
783961425 subset from a 18-fold
987634125 subset from a 16-fold
11-fold solutions
439817625 subset from a 32-fold
763498125 subset from a 20-fold
796843125 subset from a 20-fold
946837125 subset from a 16-fold
961342785 subset from a 16-fold
971238645 subset from a 16-fold
973864125 subset from a 16-fold
12-fold solutions
698341725 subset from a 24-fold
726193845 subset from a 24-fold
968417325 subset from a 18-fold
13-fold solutions
839147625 subset from a 24-fold
913276845 subset from a 24-fold
14-fold solutions
869371425 subset from a 24-fold
15-fold solutions
943678125 subset from a 24-fold
Why is it that some ninedigitals have more 'sum of squares' solutions than others?
This is due to the fact every ninedigital has its unique factorization.
Take for instance 439817625 which has nine small prime factors.
3 * 3 * 5 * 5 * 5 * 13 * 17 * 29 * 61
This allows for many combinations and thus eligible solutions whereas e.g.
123458679 = 3 * 3 * 13717631
has only three prime factors and hence impossible to express as a sum of squares.
Case N.N.1 Lowest and highest ninedigitals for A2 + B2
A and B restricted to 4-digit numbers
123456978 = 52232 + 98072 is the lowest ( from a strictly single solution )
194265378 = 97472 + 99632 is the highest ( in case of a strictly single solution )
198463725 = 99422 + 99812 is one highest version from a multi_3 solution
A and B restricted to 5-digit numbers
213458697 = 100592 + 105962 is the lowest ( ie. the highest version from a multi_2 solution )
213576498 = 101372 + 105272 is the lowest ( in case of a strictly single solution )
987641253 = 118232 + 291182 is the highest ( in case of a strictly single solution )
987654321 = 182642 + 255752 is one highest version from a multi_3 solution
Case N.N.2 Apart from squares there are cubes & other powers
as 2_tier constituents of ninedigitals
but that will be a topic for a separate investigation in the future.