A107869 - OEIS

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A107869

Column 1 of triangle A107867; a(n) = binomial( n*(n+1)/2 + n+1, n).

1, 3, 15, 120, 1365, 20349, 376740, 8347680, 215553195, 6358402050, 210980549208, 7778680504140, 315502265971620, 13961746143269400, 669413654240461560, 34569147570568156800, 1912924003884628655655, 112923282067713332728110

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..17.

PROG

(PARI) a(n)=binomial(n*(n+1)/2+n+1, n)

(Sage) [binomial(binomial(binomial(n+1, n), n-1), n-1) for n in range(1, 19)] # Zerinvary Lajos, Nov 30 2009

CROSSREFS

Cf. A107867, A107868.

Sequence in context: A260511 A093571 A093570 * A156360 A160884 A173468

Adjacent sequences: A107866 A107867 A107868 * A107870 A107871 A107872

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 04 2005

STATUS

approved