A172056 Primes p such that 2*p+-1 and 2*p+-3 are all composites.

59, 61, 103, 109, 149, 151, 163, 257, 313, 389, 401, 449, 479, 541, 569, 571, 673, 677, 709, 733, 769, 821, 823, 839, 857, 883, 919, 947, 971, 983, 1061, 1087, 1093, 1097, 1129, 1151, 1163, 1181, 1249, 1283, 1301, 1319, 1321, 1381, 1433, 1489, 1493, 1549

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 24 2010

Keywords

• nonn

Examples

			a(1)=59 because 2*59-1=117, 2*59+1=119, 2*59-3=115, 2*59+3=121 are all composites.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A002808, A068497.

Programs

Mathematica

okQ[n_]:=Union[PrimeQ[{2n+1,2n-1,2n+3,2n-3}]]=={False}; Select[Prime[Range[250]],okQ] (* Harvey P. Dale, Feb 07 2010 *)
Select[Prime[Range[300]],AllTrue[2#+{1,3,-1,-3},CompositeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 20 2015 *)

Extensions

Corrected and extended by Harvey P. Dale, Feb 07 2010