G.f. A(x) satisfies: (1 - x*A(x)) / (1 - x^2*A(x)^2)^2 = 1 - x.
A218225
G.f. A(x) satisfies: (1 - x*A(x)) / (1 - x^2*A(x)^2)^2 = 1 - x.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =23a(4) =101a(5) =480a(6) =2400a(7) =12434a(8) =66142a(9) =359112a(10) =1981904a(11) =11085198a(12) =62696874a(13) =357970472a(14) =2060459256a(15) =11943445311a(16) =69656978837a(17) =408466559630
External references
- oeis: A218225