G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k*(n-k))/2 ).

A228852

G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k*(n-k))/2 ).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =14a(4) =382a(5) =38344a(6) =12990279a(7) =14369538529

External references