G.f.: exp( Sum_{n>=1} A002426(n)^2*x^n/n ), where A002426(n) is the central trinomial coefficients.
A168598
G.f.: exp( Sum_{n>=1} A002426(n)^2*x^n/n ), where A002426(n) is the central trinomial coefficients.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =21a(4) =119a(5) =703a(6) =4515a(7) =30227a(8) =210274a(9) =1503930a(10) =11008198a(11) =82099262a(12) =622013122a(13) =4775754930a(14) =37089503826a(15) =290914775618
External references
- oeis: A168598