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Numbers that are not Mersenne primes.
3

%I #3 Mar 30 2012 17:33:50

%S 1,2,4,5,6,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,

%T 28,29,30,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,

%U 52,53,54,55,56,57,58,59,60,61,62,63,64

%N Numbers that are not Mersenne primes.

%C Numbers that are not in A000668.

%C Terms a(1) to a(2042) coincide with those of A138836, but then a(2043)=2047 <> A138836(2043)=2048.

%Y Cf. A000037, A014092. Mersenne primes: A000668.

%Y Cf. A138836.

%K easy,nonn

%O 1,2

%A _Omar E. Pol_, Nov 22 2007, Apr 05 2008