a(n) = Sum_{k=0..n} 2^(n-k) * binomial(n,k) * binomial(2*n+1,k).

A388129

a(n) = Sum_{k=0..n} 2^(n-k) * binomial(n,k) * binomial(2*n+1,k).

Terms

    a(0) =1a(1) =5a(2) =34a(3) =253a(4) =1966a(5) =15674a(6) =127100a(7) =1043165a(8) =8639350a(9) =72053110a(10) =604304636a(11) =5091508690a(12) =43061767516a(13) =365373061772

External references