A325438 Indices of primes of the form k^2 + 1 ending in 1.

5, 8, 12, 18, 20, 22, 25, 28, 30, 31, 33, 37, 39, 41, 42, 44, 46, 47, 49, 53, 54, 58, 60, 61, 63, 67, 69, 74, 84, 86, 88, 92, 93, 94, 96, 100, 102, 104, 105, 106, 109, 110, 114, 117, 119, 120, 125, 128, 133, 138, 143, 145, 146, 153, 155, 156, 158, 160, 165

Offset

1,1

Comments

This sequence is presumably infinite. See 1st comment of A002496.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

A002496(a(n)) mod 10 = 1.

Maple

P:=[seq(k mod 10, k=select(isprime, [2, seq(4*i^2+1, i=1..10000)]))]:
seq(`if`(P[i] mod 10 = 1, i, NULL), i=1..nops(P));

Crossrefs

Cf. A002496, A325437, A325439.

Sequence in context: A314410 A222802 A215284 * A314411 A359353 A360404

Adjacent sequences: A325435 A325436 A325437 * A325439 A325440 A325441

Keyword

nonn,base

Author

Martin Renner, Apr 27 2019

Status

approved