a(n) = [x^n] Product_{k=1..2*n} 1/(1 - k^2 * x).

A348081

a(n) = [x^n] Product_{k=1..2*n} 1/(1 - k^2 * x).

Terms

    a(0) =1a(1) =5a(2) =627a(3) =251498a(4) =209609235a(5) =298201326150

External references