Coefficient of x^n in the expansion of (1+x+x^2)^(3*n).
A370170
Coefficient of x^n in the expansion of (1+x+x^2)^(3*n).
Terms
- a(0) =1a(1) =3a(2) =21a(3) =156a(4) =1221a(5) =9828a(6) =80580a(7) =669294a(8) =5612805a(9) =47419905a(10) =402993396a(11) =3441242544a(12) =29502452868a(13) =253778827695
External references
- oeis: A370170