G.f.: exp( Sum_{n>=1} binomial(6*n-1, 3*n) * x^n/n ).

A213403

G.f.: exp( Sum_{n>=1} binomial(6*n-1, 3*n) * x^n/n ).

Terms

    a(0) =1a(1) =10a(2) =281a(3) =10580a(4) =457700a(5) =21475122a(6) =1062749598a(7) =54611328552

External references