A325437 -id:A325437 - cp's OEIS frontend

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

Martin Renner, Apr 27 2019

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

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

Cf. A002496, A325437, A325439.

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));

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

A325439 Indices of primes of the form k^2 + 1 ending in 7.

Original entry on oeis.org

3, 4, 6, 7, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 23, 24, 26, 27, 29, 32, 34, 35, 36, 38, 40, 43, 45, 48, 50, 51, 52, 55, 56, 57, 59, 62, 64, 65, 66, 68, 70, 71, 72, 73, 75, 76, 77, 78, 79, 80, 81, 82, 83, 85, 87, 89, 90, 91, 95, 97, 98, 99, 101, 103, 107

Offset: 1

Martin Renner, Apr 27 2019

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

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

Cf. A002496, A325437, A325438.

P:=[seq(k mod 10,k=select(isprime,[2,seq(4*i^2+1,i=1..10000)]))]:
seq(`if`(P[i] mod 10 = 7,i,NULL),i=1..nops(P));

A002496(a(n)) mod 10 = 7.

cp's OEIS Frontend

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

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