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A088502 Numbers n such that (n^2 - 5)/4 is prime. +0
4
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 (list; graph; listen)
OFFSET

1,1

FORMULA

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

EXAMPLE

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

CROSSREFS

Cf. A002327, A002328, A110013.

Sequence in context: A005763 A035034 A065155 this_sequence A081001 A075025 A075394

Adjacent sequences: A088499 A088500 A088501 this_sequence A088503 A088504 A088505

KEYWORD

easy,nonn

AUTHOR

Pierre CAMI (colettecami(AT)aol.com), Nov 13 2003

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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