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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A364868 Numbers k such that 4*k+1 is the norm of a Gaussian prime.

Original entry on oeis.org

1, 2, 3, 4, 7, 9, 10, 12, 13, 15, 18, 22, 24, 25, 27, 28, 30, 34, 37, 39, 43, 45, 48, 49, 57, 58, 60, 64, 67, 69, 70, 73, 78, 79, 84, 87, 88, 90, 93, 97, 99, 100, 102, 105, 108, 112, 114, 115, 127, 130, 132, 135, 139, 142, 144, 148, 150, 153, 154, 160, 163, 165, 168, 169
Offset: 1

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Author

Jianing Song, Aug 11 2023

Keywords

Comments

Numbers k such that 4*k+1 is a prime or the square of a prime congruent to 3 modulo 4.
If p is a Gaussian prime of norm 4*a(n)+1 (there are two up to association if a(n) is a prime, one if a(n) is the square of a prime), then for any Gaussian integer x, we have x^a(n) == 0, 1, i, -1 or -i (mod p) where i is a primitive fourth root of unity.

Examples

			2 is a term since 4*2+1 is the norm of the Gaussian prime 3.

Links

Crossrefs

Cf. A055025, A364869.
Contains 6*A024702 as a subsequence.

Programs

Formula

a(n) = (A055025(n+1) - 1)/4.
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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