[ January 15, 2015 ]
n and n_reversed are square numbers
whose roots may also be [ pseudo-] reversible
Andres Molina from Tulsa (email)
1089 is a smaller square number example whereby its reverse is also a square number
(n being not palindromic and without ending with zero).
12303690084 is the smallest square number whose reversal is also a square number
but so that their roots are pseudo-reversals amongst themselves (in base 10 at least).
What are the methods to transform nonreversible pairs into genuine reversibles ?
One way is to replace substrings using value n = 1 like follows :
09 (leading zero included) can be replaced by 1n : which is in fact 10 1
099 (leading zero included) can be replaced by 10n : which is in fact 100 1
19 can be replaced by 2n : which is in fact 20 1
199 can be replaced by 20n : which is in fact 200 1
etc.
Let me clarify with next pair of reversible squares 12303690084 & 48009630321
110922 = 111n22
and
219111 = 22n111
As you can see now the roots 111n22 and 22n111 have changed into reversibles.
Another larger example with 102030003060900000804 & 408000009060300030201
10100990202 = 101010n0202
and
20199010101 = 2020n010101
And hey presto the reversibles 101010n0202 and 2020n010101 pop up.
Can you find more such number pairs whose square roots are [pseudo-] reversals as well ?
Or larger sporadic numbers beyond those listed in A061457 and A156316 ?
When n and R(n) are equal they are of course palindromic.
Please link to Palindromic Squares.
Square Root n | (n) | Reversal(n) | Square Root R(n) [Pseudo]Reversal of Square Root n |
122 | 144 | 441 | 212 |
132 | 169 | 961 | 312 |
332 | 1089 | 9801 | 992 |
1022 | 10404 | 40401 | 2012 |
1032 | 10609 | 90601 | 3012 |
GAP |
31682 | 10036224 | 42263001 | 65012 |
205082 | 420578064 | 460875024 | 214682 |
1109222 = 111n222 | 12303690084 | 48009630321 | 2191112 = 22n1112 |
3035772 | 92158994929 | 92949985129 | 3048772 |
11009222 = 1101n222 | 1212029250084 | 4800529202121 | 21910112 = 22n10112 |
11092112 = 111n2112 | 1230349042521 | 1252409430321 °° root is palindromic ! | 11191112 °° = 112n1112 |
11109222 = 1111n222 | 1234147690084 | 4800967414321 | 21911112 = 22n11112 |
30803672 | 9488660854689 | 9864580668849 | 31407932 |
101109222 = 10111n222 | 102230743690084 | 480096347032201 | 219111012 = 22n111012 |
110091112 = 1101n1112 | 121200525010321 | 123010525002121 | 110910112 = 111n10112 |
110091222 = 1101n1222 | 121200767210884 | 488012767002121 | 220910112 = 221n10112 |
110092212 = 1101n2212 | 121202947026841 | 148620749202121 | 121910112 = 122n10112 |
110191112 = 1102n1112 | 121420807230321 | 123032708024121 | 110920112 = 111n20112 |
110910222 = 111n10222 | 123010769004484 | 484400967010321 | 220091112 = 2201n1112 |
110911112 = 111n11112 | 123012743214321 | 123412347210321 | 111091112 = 1111n1112 |
110911212 = 111n11212 | 123012965036641 | 146630569210321 | 121091112 = 1211n1112 |
110911222 = 111n11222 | 123012987218884 | 488812789210321 | 221091112 = 2211n1112 |
110912022 = 111n12022 | 123014761804804 | 408408167410321 | 202091112 = 2021n1112 |
110912112 = 111n12112 | 123014961446521 | 125644169410321 | 112091112 = 1121n1112 |
110912122 = 111n12122 | 123014983628944 | 449826389410321 | 212091112 = 2121n1112 |
110921112 = 111n21112 | 123034926436321 | 123634629430321 | 111191112 = 1112n1112 |
111009222 = 11101n222 | 123230469250084 | 480052964032321 | 219101112 = 22n101112 |
111092112 = 1111n2112 | 123414569042521 | 125240965414321 | 111911112 = 112n11112 |
111109222 = 11111n222 | 123452587690084 | 480096785254321 | 219111112 = 22n111112 |
260490132 | 678551078274169 | 961472870155876 | 310076262 |
319558912 | 1021178969603881 | 1883069698711201 | 433943512 |
101009902022 = 101010n02022 | 102030003060900000804 | 408000009060300030201 | 201990101012 = 2020n0101012 |
Related OEIS sequence
A115656 - Both n and the reverse of n are powerful(1) numbers (A001694).
A061457 - Numbers n such that n and its reversal are both squares.
A156316 - Perfect squares with property that their digit reversal is a larger perfect square.
A129914 - Irregular square reversible numbers. Numbers which when squared and written backwards give a square again, but don't satisfy reverse(n^2)=reverse(n)^2.
Index entry for sequences related to reversing digits of squares
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