a(n) = Product_{k=0..n-1} (n+4*k+3).

A384259

a(n) = Product_{k=0..n-1} (n+4*k+3).

Terms

    a(0) =1a(1) =4a(2) =45a(3) =840a(4) =21945a(5) =737280a(6) =30282525a(7) =1470268800a(8) =82380323025

External references