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A107868
Column 0 of triangle A107867; a(n) = C( n*(n-1)/2 + n + 1, n).
4
1, 2, 6, 35, 330, 4368, 74613, 1560780, 38608020, 1101716330, 35607051480, 1285063345176, 51209646652255, 2232785266876080, 105710363656182600, 5399936810873056584, 295998326072989842600, 17328840976366636057110
OFFSET
0,2
PROG
(PARI) a(n)=binomial(n*(n-1)/2+n+1, n)
CROSSREFS
Sequence in context: A305275 A326090 A197973 * A334162 A173399 A193190
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 04 2005
STATUS
approved