G.f.: Sum_{n>=0} ( (1+x)^n + (1+2*x)^n )^n * x^n.
A301465
G.f.: Sum_{n>=0} ( (1+x)^n + (1+2*x)^n )^n * x^n.
Terms
- a(0) =1a(1) =2a(2) =7a(3) =32a(4) =180a(5) =1142a(6) =8162a(7) =63807a(8) =541202a(9) =4926969a(10) =47799429a(11) =491254999a(12) =5322191407a(13) =60533874755a(14) =720300053902
External references
- oeis: A301465