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A269485

Least k > 0 such that n! + k^2 is prime.

1, 1, 1, 1, 7, 11, 7, 13, 17, 31, 13, 1, 47, 17, 19, 19, 23, 73, 43, 29, 47, 31, 43, 29, 31, 37, 167, 1, 29, 43, 79, 229, 89, 71, 137, 37, 53, 1, 79, 131, 137, 1, 71, 83, 89, 89, 53, 97, 53, 101, 59, 173, 79, 71, 353, 191, 103, 523, 229, 191, 103, 401, 67, 257

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OFFSET

0,5

COMMENTS

a(n) = A033932(n) = 1 for n in A002981.

LINKS

Jean-Marc Rebert, Table of n, a(n) for n = 0..500

EXAMPLE

a(4) = 7, because 4! + 7^2 = 73 is prime and for 0 < i < 7, 4! + i^2 is not prime.

MATHEMATICA

Table[SelectFirst[Range@ 10000, PrimeQ[n! + #^2] &], {n, 120}]

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