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 A157894 Number of composite numbers between exponents of successive Mersenne primes. 0
 0, 1, 1, 4, 3, 1, 9, 23, 22, 14, 17, 327, 73, 576, 803, 67, 820, 908, 151, 4672, 222, 1141, 7827, 1583, 1352, 19255, 37986, 22155, 19704, 77081, 499295, 95038, 369638, 130508, 1469735, 42125, 3694547, 6091617 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS a(1) = 0 since 2 is adjacent to 3 (exponent of 2nd Mersenne prime); a(2) = 1 since 4 is between 3 and 5 (exponent of 3rd Mersenne prime); a(3) = 1 since 6 is between 5 and 7 (exponent of 4th Mersenne prime); a(4) = 4 since 8, 9, 10, and 12 are between 7 and 13 (exponent of 5th Mersenne prime). LINKS MATHEMATICA 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 *) CROSSREFS Sequence in context: A123160 A109692 A039758 * A172106 A128813 A109062 Adjacent sequences:  A157891 A157892 A157893 * A157895 A157896 A157897 KEYWORD nonn AUTHOR Jani Melik, Mar 08 2009, Apr 02 2009 EXTENSIONS a(34) - a(38) from Robert G. Wilson v, Mar 14 2009 STATUS approved

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Last modified June 14 21:27 EDT 2021. Contains 345041 sequences. (Running on oeis4.)