A066942 Numbers k such that gcd(prime(k+1) + 1, prime(k) + 1) = 6.

9, 15, 16, 23, 32, 39, 40, 51, 54, 55, 56, 71, 76, 86, 96, 97, 102, 103, 107, 108, 118, 119, 123, 139, 160, 161, 164, 165, 170, 184, 185, 194, 195, 199, 200, 208, 218, 219, 227, 238, 245, 252, 255, 267, 290, 291, 292, 293, 298, 311, 312, 329, 342, 345, 349

Offset: 1

Author

Benoit Cloitre, Jan 24 2002

Keywords

• nonn

Comments

Numbers k such that A063086(k) = 6. - Andrew Howroyd, Dec 10 2024

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A063086, A066940, A066941, A066943, A066944, A067603, A067604.

Programs

Mathematica

Select[ Range[400], GCD[ Prime[ # + 1] + 1, Prime[ # ] + 1] == 6 & ]
Drop[Position[Partition[Prime[Range[400]],2,1],?(GCD@@(#+1)==6&)],2]//Flatten (* _Harvey P. Dale, Nov 08 2022 *)

PARI

isok(k) = { gcd(prime(k+1) + 1, prime(k) + 1) == 6 } \\ Harry J. Smith, Apr 10 2010

Extensions

Edited by Robert G. Wilson v, Feb 01 2002