A030685 Smallest nontrivial extension of n-th square which is a prime.

11, 41, 97, 163, 251, 367, 491, 641, 811, 1009, 1213, 1447, 1693, 19661, 2251, 25621, 2897, 32411, 3613, 4001, 44111, 48413, 5297, 57637, 6257, 6761, 7297, 7841, 8419, 9001, 9613, 10243, 10891, 115613, 12251, 12967, 13691, 14447

Offset

1,1

Comments

Extensions here cannot contain leading 0's, otherwise we would have a(14)=19603. - Sean A. Irvine, Apr 05 2020

Links

Table of n, a(n) for n=1..38.

Prog

(PARI) a(n) = {my(k=1); while(!isprime(x=eval(concat(Str(n^2), Str(k)))), k++); x; } \\ Michel Marcus, Apr 06 2020

Crossrefs

Cf. A000290 (squares).

Sequence in context: A158187 A239462 A065145 * A356260 A386030 A132208

Adjacent sequences: A030682 A030683 A030684 * A030686 A030687 A030688

Keyword

nonn,base

Author

Patrick De Geest

Status

approved