

A168158


Indices n for which A168157(n) is prime.


0



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
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OFFSET

1,1


COMMENTS

If n=primepi(2^k1) 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



