a(n) = binomial(6*n,2*n)/3, n>0, a(0)=1.

A259613

a(n) = binomial(6*n,2*n)/3, n>0, a(0)=1.

Terms

    a(0) =1a(1) =5a(2) =165a(3) =6188a(4) =245157a(5) =10015005a(6) =417225900a(7) =17620076360a(8) =751616304549

External references