WON TOPIC 68

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All the left-truncatable primes For archiving purposes I created a page displaying all the 4260 left-truncatable primes by courtesy of Eric Weisstein, creator of the list. No need to program the topic as M. F. Hasler did already the work in [ Nov 07, 2018 ]. I retrieved the Pari/gp code from the OEIS database. It is amazing how he achieved it with this very concise oneliners ! { A024785 = vector(25, n, p=vecsort(concat(apply(p->select(isprime, vector(9, i, i10^(n-1)+p)), if(n>1, p))))) } A024785 yields the list of rows (n-digit terms, n = 1..25). Use concat(%) to flatten. and for the number (#) of solutions for each digitlength is given by A050987 { A050987 = vector(25, n, #p=concat(apply(p->select(isprime, vector(9, i, i10^(n-1)+p)), if(n>1, p)))) }
A000068 Prime Curios! Prime Puzzle Wikipedia 68 Le Nombre 68 Numberland 68

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Numbers

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All the left-truncatable primes

For archiving purposes I created a page displaying all
the 4260 left-truncatable primes
by courtesy of Eric Weisstein, creator of the list.

No need to program the topic as M. F. Hasler did already the work in [ Nov 07, 2018 ].
I retrieved the Pari/gp code from the OEIS database.
It is amazing how he achieved it with this very concise oneliners !

{
A024785 = vector(25, n, p=vecsort(concat(apply(p->select(isprime,
vector(9, i, i*10^(n-1)+p)), if(n>1, p)))))
}

A024785 yields the list of rows (n-digit terms, n = 1..25). Use concat(%) to flatten.

and for the number (#) of solutions for each digitlength is given by A050987

{
A050987 = vector(25, n, #p=concat(apply(p->select(isprime,
vector(9, i, i*10^(n-1)+p)), if(n>1, p))))
}

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Patrick De Geest - Belgium

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