a(n) = Sum_{k=0..n} 2^(n-k) * binomial(k+2,2) * binomial(2*k,2*(n-k)).
A391876
a(n) = Sum_{k=0..n} 2^(n-k) * binomial(k+2,2) * binomial(2*k,2*(n-k)).
Terms
- a(0) =1a(1) =3a(2) =12a(3) =82a(4) =339a(5) =1461a(6) =6198a(7) =24732a(8) =97557a(9) =377095a(10) =1431792a(11) =5370102a(12) =19904711a(13) =73046121a(14) =265779354a(15) =959669856a(16) =3441865065a(17) =12270185691a(18) =43506695476a(19) =153510593754a(20) =539253893883
External references
- oeis: A391876