# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a191618 Showing 1-1 of 1 %I A191618 #9 Aug 03 2014 14:01:31 %S A191618 0,1,1,1,2,1,11,2,2,1,13,2,4,22,2,1,2,2,43,4,2,13,2,1,13,1,2,46,8,29, %T A191618 83,2,8,34,1,11,19,31,25,7,38,31,31,76,52,31,43,32,13,92,2,1,59,22,1, %U A191618 16,19,11,16,74,8,13,8,74,2,121,20,49,85,134,116,16 %N A191618 Least a such that (2^n+a)*2^n - 1 is prime. %H A191618 Pierre CAMI, Table of n, a(n) for n = 1..5000 %t A191618 Table[a = 0; While[! PrimeQ[(2^n + a)*2^n - 1], a++]; a, {n, 100}] (* _T. D. Noe_, Jun 11 2011 *) %Y A191618 Cf. A191617, A191619, A191620, A191621. %K A191618 nonn %O A191618 1,5 %A A191618 _Pierre CAMI_, Jun 09 2011 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE