a(n) = (1/n) * Sum_{k=0..n-1} C(n,k) * C(n,k+1) * (n-1)^k.
A099169
a(n) = (1/n) * Sum_{k=0..n-1} C(n,k) * C(n,k+1) * (n-1)^k.
Terms
- a(0) =1a(1) =2a(2) =11a(3) =100a(4) =1257a(5) =20076a(6) =387739a(7) =8766248a(8) =226739489a(9) =6595646860a(10) =212944033051
External references
- oeis: A099169