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A120487 Denominator of 1^n/n + 2^n/(n-1) + 3^n/(n-2) +...+ (n-1)^n/2 + n^n/1. 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

LINKS

Table of n, a(n) for n=1..31.

FORMULA

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

MATHEMATICA

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

CROSSREFS

Cf. A115071, A027612, A031971, A002805.

Cf. A001008, A002805.

Sequence in context: A214011 A081369 A147967 * A237873 A069220 A062957

Adjacent sequences:  A120484 A120485 A120486 * A120488 A120489 A120490

KEYWORD

frac,nonn

AUTHOR

Alexander Adamchuk, Jul 22 2006

STATUS

approved

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Last modified April 18 14:05 EDT 2014. Contains 240720 sequences.