G.f. satisfies: A(x) = exp( Sum_{n>=1} x^n/n * Sum_{k=0..2*n} A084606(n,k)^2 * x^k * A(x)^k ), where A084606(n,k) = [x^k] (1 + 2*x + 2*x^2)^n.
A218299
G.f. satisfies: A(x) = exp( Sum_{n>=1} x^n/n * Sum_{k=0..2*n} A084606(n,k)^2 * x^k * A(x)^k ), where A084606(n,k) = [x^k] (1 + 2*x + 2*x^2)^n.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =21a(4) =109a(5) =573a(6) =3209a(7) =18425a(8) =108649a(9) =652425a(10) =3979805a(11) =24583853a(12) =153488501a(13) =966993893a(14) =6139832385a(15) =39249227569a(16) =252400089361
External references
- oeis: A218299