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 A137648 a(n) = Sum_{k=0..n} C(k^2, k) * C(k^2, n-k). 0
 1, 1, 7, 108, 2612, 85298, 3501504, 172989880, 9987924928, 659768790882, 49065577842538, 4056413252138692, 369030922581806616, 36634832808175143734, 3940779041158898056286, 456592594401713997379344 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS MATHEMATICA Table[Sum[Binomial[k^2, k]Binomial[k^2, n-k], {k, 0, n}], {n, 0, 20}] (* Harvey P. Dale, Dec 05 2012 *) PROG (PARI) a(n)=sum(k=0, n, binomial(k^2, k)*binomial(k^2, n-k)) CROSSREFS Sequence in context: A218819 A033516 A130629 * A106977 A142480 A202515 Adjacent sequences:  A137645 A137646 A137647 * A137649 A137650 A137651 KEYWORD nonn AUTHOR Paul D. Hanna, Jan 31 2008 STATUS approved

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Last modified August 13 22:14 EDT 2020. Contains 336458 sequences. (Running on oeis4.)