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A107871 Column 0 of triangle A107870; a(n) = C( n*(n-1)/2 + n+2, n). 2
1, 3, 10, 56, 495, 6188, 100947, 2035800, 48903492, 1362649145, 43183019880, 1533058025824, 60246643120300, 2595612872743443, 121623751733457400, 6156937298378625264, 334817778672726215400, 19463553270556728904725 (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+2, n)

CROSSREFS

Cf. A107870, A107872.

Sequence in context: A301920 A203416 A002218 * A111270 A307906 A274585

Adjacent sequences:  A107868 A107869 A107870 * A107872 A107873 A107874

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 04 2005

STATUS

approved

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Last modified December 5 21:00 EST 2019. Contains 329779 sequences. (Running on oeis4.)