A259978 Terms in A053177 that are relatively prime to 3.

35, 95, 119, 143, 203, 215, 275, 299, 335, 395, 455, 515, 527, 539, 623, 635, 695, 707, 767, 779, 803, 899, 923, 935, 959, 1007, 1043, 1115, 1127, 1139, 1175, 1199, 1235, 1295, 1355, 1403, 1547, 1595, 1643, 1655, 1679, 1715, 1727, 1763, 1775, 1859, 1883, 1895

Offset

1,1

Links

Lars Blomberg, Table of n, a(n) for n = 1..4332

R. P. Boas & N. J. A. Sloane, Correspondence, 1974

Formula

a(n) = 2*A275770(n) + 1. - Hilko Koning, Jul 23 2018

Mathematica

Select[2 Prime@ Range@ 162 + 1, CompositeQ@ # && GCD[3, #] == 1 &] (* Michael De Vlieger, Jul 13 2015 *)

Prog

(PARI) isok(n) = (n % 2) && !isprime(n) && isprime((n-1)/2) && (gcd(n, 3) == 1); \\ Michel Marcus, Jul 28 2018

Crossrefs

Cf. A053177.

Sequence in context: A020164 A146206 A350196 * A044222 A044603 A063795

Adjacent sequences: A259975 A259976 A259977 * A259979 A259980 A259981

Keyword

nonn,easy

Author

N. J. A. Sloane, Jul 12 2015, following a suggestion from R. P. Boas, May 19 1974

Extensions

More terms from Lars Blomberg, Jul 13 2015

Status

approved