cp's OEIS Frontend

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.

A088502 Numbers n such that (n^2 - 5)/4 is prime.

Original entry on oeis.org

5, 7, 9, 11, 13, 17, 19, 21, 23, 27, 31, 33, 39, 41, 43, 49, 53, 57, 61, 63, 71, 77, 79, 83, 89, 91, 93, 97, 101, 107, 109, 111, 113, 119, 121, 129, 131, 133, 137, 141, 153, 167, 171, 173, 179, 187, 189, 193, 201, 203, 207, 229, 231, 241, 251, 253, 261, 263, 269
Offset: 1

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Author

Pierre CAMI, Nov 13 2003

Keywords

Comments

Under Bunyakovsky's conjecture this sequence is infinite. - Charles R Greathouse IV, Dec 28 2011

Examples

			(23*23 - 5)/4 = 131, 131 is prime, 23 is the 9th n of the sequence.
		

Crossrefs

Programs

Formula

a(n) = 2*A002328(n) - 1 = Sqrt(A110013(n)). - Ray Chandler, Sep 07 2005