a(n) = Sum_{k=0..n} 3^k * binomial(n+3,k) * binomial(n+3,k+3).
A387340
a(n) = Sum_{k=0..n} 3^k * binomial(n+3,k) * binomial(n+3,k+3).
Terms
- a(0) =1a(1) =16a(2) =175a(3) =1640a(4) =14189a(5) =117152a(6) =939036a(7) =7379040a(8) =57188010a(9) =438810592a(10) =3342302821a(11) =25316084248a(12) =190937278805
External references
- oeis: A387340