A332200 Limerick primes: Primes with decimal representation of the form AABBA, with B < A.

33113, 33223, 77447, 77557, 99119, 99559, 13134413, 13138813, 17172217, 17177717, 19191119, 19192219, 19194419, 1919111119, 1919161619, 1919171719, 2121111121, 23231123, 23237723, 2323131323, 27277727, 2727131327, 29295529, 29297729, 2929191929, 31311131, 3131232331, 3131282831

Offset

1,1

Comments

There are other possible definitions of what could be considered a "limerick prime": One may require A and B just to be single digits (Cook link), one might restrict them to have length |B| < |A|, purists might require them to have 9 resp. 5 digits (and not necessarily be the same, i.e.: A, A', B, B', A", where As and Bs rhyme or end in the same digit, cf. Kesteloot tweet) or to have that number of syllables when spelled out in English: a(6) = 99559 gives the number of syllables per line in a limerick.

Links

Table of n, a(n) for n=1..28.

J. D. Cook, Limerick primes, March 8, 2011.

Lawrence Kesteloot, A #LimerickPrime, on twitter, Oct. 6, 2015.

Lawrence Kesteloot, Limerick prime, on GitHub, 2015.

Greg Ross, Trivium 39: Sonnet prime, FutilityCloset, March 3, 2011.

Mathematica

Select[Flatten@ Table[FromDigits@ Flatten@ Map[IntegerDigits, {a, a, b, b, a}], {a, 31}, {b, 0, a - 1}], PrimeQ] (* Michael De Vlieger, Apr 30 2020 *)

Prog

(PARI) print_upto(n, i=1)=until(i++>n, for(j=0, i-1, isprime(p=eval(Str(i, i, j, j, i)))&&print1(p", ")))

Crossrefs

Sequence in context: A118280 A062682 A094889 * A031660 A252291 A203619

Adjacent sequences: A332197 A332198 A332199 * A332201 A332202 A332203

Keyword

nonn,base

Author

M. F. Hasler, Apr 18 2020

Status

approved