a(n) = (1/(2*n+1)) * Sum_{k=0..n} k^4 * (2*k+1) * binomial(3*n-k,n-k).
A390973
a(n) = (1/(2*n+1)) * Sum_{k=0..n} k^4 * (2*k+1) * binomial(3*n-k,n-k).
Terms
- a(0) =0a(1) =1a(2) =19a(3) =173a(4) =1278a(5) =8684a(6) =56772a(7) =364133a(8) =2313340a(9) =14630265a(10) =92364159a(11) =583015884a(12) =3682815128a(13) =23293263864a(14) =147556696784a(15) =936334841109
External references
- oeis: A390973