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A089512 Denominators used in the computation of the column sequences of array A078739 ((2,2)-Stirling2). 1
1, 2, 1, 18, 6, 360, 90, 12600, 2520, 680400, 113400, 52390800, 7484400, 5448643200, 681080400, 735566832000, 81729648000, 125046361440000, 12504636144000, 26134689540960000, 2375880867360000, 6585941764321920000 (list; graph; refs; listen; history; internal format)
OFFSET

2,2

COMMENTS

See A089511 for the column sequence computation of A078739.

FORMULA

a(n)=LCM(seq(denominator(b(n, m)), m=1..n-1)), n>=2, where b(n, m) is defined like A089511(n, m) but without the factor D(n) and LCM stands for the least common multiple of a set of numbers.

a(n)=(sqrt(2)*n!/(8*2^(n/2)))*((n^2+4n+2*sqrt(2)+3)-(n^2+4n-2*sqrt(2)+3)*(-1)^n) [offset 0]. - Paul Barry (pbarry(AT)wit.ie), Sep 04 2007

CROSSREFS

Sequence in context: A013072 A012895 A013077 * A089014 A063426 A181870

Adjacent sequences:  A089509 A089510 A089511 * A089513 A089514 A089515

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Dec 01 2003

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Last modified February 17 12:38 EST 2012. Contains 206021 sequences.