A079703 Numbers 4p where p is prime and 2p+1 and 4p+1 are composite.

68, 76, 124, 188, 236, 244, 284, 404, 412, 428, 436, 548, 596, 604, 628, 668, 724, 788, 844, 892, 908, 916, 964, 1028, 1052, 1076, 1084, 1132, 1244, 1252, 1268, 1324, 1348, 1388, 1396, 1412, 1468, 1516, 1532, 1556, 1588, 1604, 1684, 1756, 1796, 1828, 1844

Offset

0,1

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

2*17+1=35, 4*17+1=69, therefore 68 is in the sequence.

Mathematica

Select[4*Prime[Range[90]], AllTrue[{#/2, #}+1, CompositeQ]&] (* Harvey P. Dale, Dec 28 2023 *)

Prog

(PARI) forprime (p=3, 200, if (!isprime(2*p+1) && !isprime(4*p+1), print1(4*p", ")))

Crossrefs

Subsequence of A005277

Sequence in context: A153831 A306113 A058980 * A281235 A097760 A180937

Adjacent sequences: A079700 A079701 A079702 * A079704 A079705 A079706

Keyword

nonn

Author

Jon Perry, Jan 31 2003

Extensions

More terms from Michel Marcus, Mar 17 2014

Status

approved