Coefficient of x^n in (1 + n*x + n*x^3)^n.
A307903
Coefficient of x^n in (1 + n*x + n*x^3)^n.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =36a(4) =448a(5) =6875a(6) =124956a(7) =2624293a(8) =62537728a(9) =1667191653a(10) =49158400000
External references
- oeis: A307903