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A030685 Smallest nontrivial extension of n-th square which is a prime. 1
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 (list; graph; refs; listen; history; text; internal format)
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 * A132208 A233434 A261538

Adjacent sequences:  A030682 A030683 A030684 * A030686 A030687 A030688

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified October 18 01:39 EDT 2021. Contains 348065 sequences. (Running on oeis4.)