a(n) = Sum_{k=0..n} Stirling2(n,k) * binomial(4*k,k) / (3*k + 1).

A346765

a(n) = Sum_{k=0..n} Stirling2(n,k) * binomial(4*k,k) / (3*k + 1).

Terms

    a(0) =1a(1) =1a(2) =5a(3) =35a(4) =301a(5) =2980a(6) =32824a(7) =394119a(8) =5089387a(9) =70008606a(10) =1018551386a(11) =15586572831a(12) =249761256325

External references