a(0)=1; for n > 0, a(n)=sum(binomial(n,k)*binomial(n+k,k+1)*binomial(n+k+1,k),k=0..n)/n.
A075132
a(0)=1; for n > 0, a(n)=sum(binomial(n,k)*binomial(n+k,k+1)*binomial(n+k+1,k),k=0..n)/n.
Terms
- a(0) =1a(1) =4a(2) =33a(3) =356a(4) =4415a(5) =59690a(6) =855925a(7) =12809620a(8) =198034395a(9) =3140695856a(10) =50845026815a(11) =837207042270
External references
- oeis: A075132