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A108861
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Numbers n such that n divides the sum of the digits of 2^n * n!.
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0
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1, 2, 3, 5, 6, 9, 27, 81, 126, 159, 205, 252, 254, 267, 285, 675, 1053, 1086, 1125, 1146, 2007, 5088, 5382, 5448, 14652, 23401, 23574, 24009, 41004, 66789, 67482, 111480, 866538
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OFFSET
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1,2
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COMMENTS
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Next term after 5448 is greater than 10,000.
a(34) > 10^6. [From D. S. McNeil, Mar 03 2009]
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LINKS
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Table of n, a(n) for n=1..33.
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EXAMPLE
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675 is a term because the sum of the digits of 2^675 * 675!, 7425, is divisible by 675.
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MATHEMATICA
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Do[If[Mod[Plus @@ IntegerDigits[2^n * n! ], n] == 0, Print[n]], {n, 1, 10000}]
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CROSSREFS
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Sequence in context: A079371 A131761 A055690 * A051896 A061939 A029503
Adjacent sequences: A108858 A108859 A108860 * A108862 A108863 A108864
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KEYWORD
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base,hard,more,nonn
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AUTHOR
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Ryan Propper (rpropper(AT)stanford.edu), Jul 11 2005
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EXTENSIONS
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a(25) - a(33) from D. S. McNeil, Mar 03 2009
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STATUS
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approved
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