Catalan-like formula: a(n) = binomial(6*n, 3*n+1)/(9*n+6).

A065424

Catalan-like formula: a(n) = binomial(6*n, 3*n+1)/(9*n+6).

Terms

    a(0) =1a(1) =33a(2) =1326a(3) =59432a(4) =2851425a(5) =143291610a(6) =7446255180a(7) =396893583792

External references