a(0) = 1 and a(n) = Sum_{k = 0..3*n} n/(n + 2*k)*binomial(n + 2*k,k) for n >= 1.

A352276

a(0) = 1 and a(n) = Sum_{k = 0..3*n} n/(n + 2*k)*binomial(n + 2*k,k) for n >= 1.

Terms

    a(0) =1a(1) =9a(2) =625a(3) =58785a(4) =5986993a(5) =633580634a(6) =68611922731

External references