%I A117293
%S A117293 11,111,11111,1111111,1111111111111,11111111111111111,
%T A117293 1111111111111111111,1111111111111111111111111111111,
%U A117293 1111111111111111111111111111111111111111111111111111111111111
%N A117293 Mersenne primes written in binary.
%C A117293 The number of bits in a(n) is equal to A000043(n). - Omar E. Pol (info(AT)polprimos.com), 
               Feb 22 2008
%D A117293 http://en.wikipedia.org/wiki/Mersenne_prime
%e A117293 Third mersenne prime is 31, i.e. 11111 in binary
%Y A117293 Cf. A000043, A000668.
%Y A117293 Sequence in context: A136982 A083441 A031974 this_sequence A015468 A037842 
               A131293
%Y A117293 Adjacent sequences: A117290 A117291 A117292 this_sequence A117294 A117295 
               A117296
%K A117293 base,nonn
%O A117293 1,1
%A A117293 Jacob Vecht (vecht(AT)alcielo.com), Apr 23 2006