a(n) = Sum_{k=0..2n-1} C(2n-1,k)*trinomial(n,k) for n>0 with a(0)=1.
A132306
a(n) = Sum_{k=0..2n-1} C(2n-1,k)*trinomial(n,k) for n>0 with a(0)=1.
Terms
- a(0) =1a(1) =2a(2) =18a(3) =179a(4) =1874a(5) =20202a(6) =221943a(7) =2470827a(8) =27777618a(9) =314642708a(10) =3585365618a(11) =41054041602a(12) =471980219543
External references
- oeis: A132306