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A120487
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Denominator of 1^n/n + 2^n/(n-1) + 3^n/(n-2) +...+ (n-1)^n/2 + n^n/1.
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0
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1, 2, 3, 12, 5, 20, 35, 280, 63, 2520, 385, 27720, 6435, 8008, 45045, 720720, 85085, 4084080, 969969, 739024, 29393, 5173168, 7436429, 356948592, 42902475, 2974571600, 717084225, 80313433200, 215656441, 2329089562800, 4512611027925
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OFFSET
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1,2
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COMMENTS
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Numerator is A115071[n].
Also a(n) is denominator of (n+1)^(n+1) * ( H(n+1) - 1 ), where H(k) is harmonic number, H(k) = Sum[ 1/i, {i,1,k} ] = A001008(k)/A002805(k). - Alexander Adamchuk, Jan 02 2007
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LINKS
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Table of n, a(n) for n=1..31.
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FORMULA
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a(n) = Denominator[Sum[k^n/(n-k+1),{k,1,n}]].
a(n) = Denominator[ (n+1)^(n+1) * Sum[ 1/i,{i,2,n+1} ] ]. - Alexander Adamchuk, Jan 02 2007
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MATHEMATICA
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Denominator[Table[Sum[k^n/(n-k+1), {k, 1, n}], {n, 1, 50}]]
Table[ Denominator[ (n+1)^(n+1) * Sum[ 1/i, {i, 2, n+1} ] ], {n, 1, 40} ] - Alexander Adamchuk, Jan 02 2007
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CROSSREFS
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Cf. A115071, A027612, A031971, A002805.
Cf. A001008, A002805.
Sequence in context: A214011 A081369 A147967 * A069220 A062957 A124444
Adjacent sequences: A120484 A120485 A120486 * A120488 A120489 A120490
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KEYWORD
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frac,nonn
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AUTHOR
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Alexander Adamchuk, Jul 22 2006
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STATUS
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approved
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