a(n) = A121680(n)/(n+1) = [x^n] (1 + x*(1+x)^(n+1) )^(n+1) / (n+1).
A121681
a(n) = A121680(n)/(n+1) = [x^n] (1 + x*(1+x)^(n+1) )^(n+1) / (n+1).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =19a(4) =131a(5) =1136a(6) =11670a(7) =138727a(8) =1864711a(9) =27843874a(10) =456081803a(11) =8114074563a(12) =155519173031
External references
- oeis: A121681