a(0) = 1 and a(n) = (1/n) * Sum_{k=1..n} 3^k * binomial(n,k) * binomial(n^2,k-1) for n > 0.
A336578
a(0) = 1 and a(n) = (1/n) * Sum_{k=1..n} 3^k * binomial(n,k) * binomial(n^2,k-1) for n > 0.
Terms
- a(0) =1a(1) =3a(2) =21a(3) =408a(4) =14799a(5) =817743a(6) =61621806a(7) =5921141502a(8) =694008501627
External references
- oeis: A336578