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Table of n, a(n) for n=0..17.
(PARI) a(n)=sum(k=0, n, binomial(k*(k+1)/2, k)*binomial(k*(k+1)/2, n-k))
Sequence in context: A028853 A118795 A099700 * A231498 A168602 A000798
Adjacent sequences: A137643 A137644 A137645 * A137647 A137648 A137649
Paul D. Hanna, Jan 31 2008