a(n) = Sum_{k=0..n} C(n + 2*k, 3*k) * C(3*k, 2*k).
A243116
a(n) = Sum_{k=0..n} C(n + 2*k, 3*k) * C(3*k, 2*k).
Terms
- a(0) =1a(1) =4a(2) =28a(3) =220a(4) =1816a(5) =15424a(6) =133456a(7) =1169872a(8) =10354528a(9) =92331904a(10) =828204928a(11) =7464652672a(12) =67547774464a(13) =613295870464
External references
- oeis: A243116