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A325438
Indices of primes of the form k^2 + 1 ending in 1.
2
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
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
KEYWORD
nonn,base
AUTHOR
Martin Renner, Apr 27 2019
STATUS
approved