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%I #8 Mar 13 2015 22:49:23
%S 0,1,1,4,3,1,9,23,22,14,17,327,73,576,803,67,820,908,151,4672,222,
%T 1141,7827,1583,1352,19255,37986,22155,19704,77081,499295,95038,
%U 369638,130508,1469735,42125,3694547,6091617
%N Number of composite numbers between exponents of successive Mersenne primes.
%C a(1) = 0 since 2 is adjacent to 3 (exponent of 2nd Mersenne prime);
%C a(2) = 1 since 4 is between 3 and 5 (exponent of 3rd Mersenne prime);
%C a(3) = 1 since 6 is between 5 and 7 (exponent of 4th Mersenne prime);
%C a(4) = 4 since 8, 9, 10, and 12 are between 7 and 13 (exponent of 5th Mersenne prime).
%t mp={ (*A000043 *) }; lst = {}; Do[ c = mp[[n + 1]] - mp[[n]] - PrimePi@ mp[[n + 1]] + PrimePi@ mp[[n]]; AppendTo[lst, c], {n, 38}]; lst (* _Robert G. Wilson v_, Mar 14 2009 *)
%Y A002808, A000043, A046933
%K nonn
%O 1,4
%A _Jani Melik_, Mar 08 2009, Apr 02 2009
%E a(34) - a(38) from _Robert G. Wilson v_, Mar 14 2009
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