login
A032363
Numbers k such that 27*2^k+1 is prime.
2
2, 4, 7, 16, 19, 20, 22, 26, 40, 44, 46, 47, 50, 56, 59, 64, 92, 175, 215, 275, 407, 455, 1076, 1090, 3080, 3322, 6419, 7639, 19360, 30500, 38770, 44164, 50696, 114760, 117784, 153847, 160874, 178739, 379880, 405514, 672007, 974752, 1164664, 1476347, 2218064
OFFSET
1,1
PROG
(PARI) is(n)=ispseudoprime(27*2^n+1) \\ Charles R Greathouse IV, Jun 06 2017
CROSSREFS
Cf. A050539 = 27*2^n-1 is prime.
Sequence in context: A364596 A280031 A135131 * A303749 A239390 A338647
KEYWORD
nonn,hard
EXTENSIONS
More terms from Hugo Pfoertner, Jun 20 2003
More terms from Hugo Pfoertner, Aug 17 2004
Added more terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013
STATUS
approved