a(n) = [x^n] (1-x)^(3n+1)/(n+1) * Sum_{k>=0} C(n+k-1,k)^3*x^k.
A183205
a(n) = [x^n] (1-x)^(3n+1)/(n+1) * Sum_{k>=0} C(n+k-1,k)^3*x^k.
Terms
- a(0) =1a(1) =2a(2) =16a(3) =190a(4) =2768a(5) =45584a(6) =814728a(7) =15439974a(8) =305760400a(9) =6265985440a(10) =131980086368
External references
- oeis: A183205