a(0) = 0; a(n) = 3^(n-1) + (1/n) * Sum_{k=1..n-1} binomial(n,k)^2 * 3^(k-1) * (n-k) * a(n-k).
A333982
a(0) = 0; a(n) = 3^(n-1) + (1/n) * Sum_{k=1..n-1} binomial(n,k)^2 * 3^(k-1) * (n-k) * a(n-k).
Terms
- a(0) =0a(1) =1a(2) =5a(3) =48a(4) =909a(5) =28836a(6) =1371384a(7) =91308708a(8) =8106024861a(9) =925225277004
External references
- oeis: A333982