a(n) = Sum_{k=0..n} 2^k * 3^(n-k) * binomial(n+1,k) * binomial(n+1,n-k).
A387368
a(n) = Sum_{k=0..n} 2^k * 3^(n-k) * binomial(n+1,k) * binomial(n+1,n-k).
Terms
- a(0) =1a(1) =10a(2) =93a(3) =860a(4) =7985a(5) =74550a(6) =699685a(7) =6597400a(8) =62457921a(9) =593346050a(10) =5653702637a(11) =54012503220a(12) =517192500721
External references
- oeis: A387368