G.f. D(x) satisfies: D(x) = (1 + x*D(x))*(1 + 2*x*D(x))*(1 + 3*x*D(x)).
A071878
G.f. D(x) satisfies: D(x) = (1 + x*D(x))*(1 + 2*x*D(x))*(1 + 3*x*D(x)).
Terms
- a(0) =1a(1) =6a(2) =47a(3) =420a(4) =4058a(5) =41286a(6) =435739a(7) =4726644a(8) =52373294a(9) =590247900a(10) =6744908118a(11) =77969430864a(12) =910131055980
External references
- oeis: A071878