A168158 Indices n for which A168157(n) is prime.

7, 10, 11, 12, 15, 18, 29, 35, 45, 49, 51, 55, 58, 65, 80, 82, 84, 89, 93, 95, 114, 119, 128, 130, 140, 142, 149, 155, 157, 160, 166, 171, 173, 175, 191, 192, 209, 210, 218, 235, 240, 251, 262, 263, 269, 280, 305, 315, 321, 324, 328, 337, 341, 344, 345, 363, 372

Offset

1,1

Comments

If n=primepi(2^k-1) is in this sequence, then A158671(k) is prime. This happens for k=5, 6, 18,... corresponding to n=11, 18, 23000,... (cf. link).

Links

Table of n, a(n) for n=1..57.

C. Caldwell, G. L. Honaker, Editors: Prime curio!: 18 by J. Vos Post.

Prog

(PARI) s=0; for(n=1, 999, isprime(n*#(b=binary(prime(n)))-s+=norml2(b)) & print1(n", "))

Crossrefs

Sequence in context: A192268 A117319 A120645 * A278738 A060228 A190231

Adjacent sequences: A168155 A168156 A168157 * A168159 A168160 A168161

Keyword

nonn

Author

M. F. Hasler, Nov 21 2009

Status

approved