a(n) = Sum_{k=0..n} (k+1) * 2^k * 3^(n-k) * binomial(k,n-k)^2.
A391677
a(n) = Sum_{k=0..n} (k+1) * 2^k * 3^(n-k) * binomial(k,n-k)^2.
Terms
- a(0) =1a(1) =4a(2) =24a(3) =176a(4) =1052a(5) =6624a(6) =41632a(7) =256768a(8) =1584912a(9) =9738944a(10) =59592704a(11) =363733248a(12) =2214201280a(13) =13448074240a(14) =81518607360a(15) =493270777856
External references
- oeis: A391677