a(n) = (2*n+5)!!/5!!, related to A001147 (odd double factorials).

A051579

a(n) = (2*n+5)!!/5!!, related to A001147 (odd double factorials).

Terms

    a(0) =1a(1) =7a(2) =63a(3) =693a(4) =9009a(5) =135135a(6) =2297295a(7) =43648605a(8) =916620705a(9) =21082276215a(10) =527056905375

External references