a(n) = Sum_{k=0..n} (-1)^k * binomial(3*n-k+4,n-k).
A390591
a(n) = Sum_{k=0..n} (-1)^k * binomial(3*n-k+4,n-k).
Terms
- a(0) =1a(1) =6a(2) =37a(3) =230a(4) =1444a(5) =9142a(6) =58277a(7) =373596a(8) =2406241a(9) =15559016a(10) =100942636a(11) =656768216a(12) =4283802832a(13) =28002175286a(14) =183395014053
External references
- oeis: A390591