a(n) = (Sum_{k=0..n-1}(145*k^2+104*k+18)*C(2k,k)*C(3k,k)^2/(2k+1))/(6n*(2n-1)*C(3n,n)).
A371652
a(n) = (Sum_{k=0..n-1}(145*k^2+104*k+18)*C(2k,k)*C(3k,k)^2/(2k+1))/(6n*(2n-1)*C(3n,n)).
Terms
- a(0) =1a(1) =3a(2) =29a(3) =399a(4) =6514a(5) =117711a(6) =2275251a(7) =46139015a(8) =969837866a(9) =20962468086a(10) =463305649245
External references
- oeis: A371652