G.f.: A(x) = 1 + x*A(x)^3 / ( A(I*x)*A(-I*x) ), where I^2 = -1.
A216681
G.f.: A(x) = 1 + x*A(x)^3 / ( A(I*x)*A(-I*x) ), where I^2 = -1.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =17a(4) =85a(5) =333a(6) =1883a(7) =13153a(8) =76329a(9) =363033a(10) =2304867a(11) =17067553a(12) =104686957a(13) =534812789a(14) =3558451915a(15) =27086552833a(16) =170930393745a(17) =906063493617
External references
- oeis: A216681