G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n,k) * binomial(n^2,k^2) ).
A207139
G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n,k) * binomial(n^2,k^2) ).
Terms
- a(0) =1a(1) =2a(2) =7a(3) =147a(4) =14481a(5) =6183605a(6) =19196862399
External references
- oeis: A207139