E.g.f. 1/(1 - tan(2*x))^(1/2).

A235131

E.g.f. 1/(1 - tan(2*x))^(1/2).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =23a(4) =201a(5) =2401a(6) =33723a(7) =564983a(8) =10832721a(9) =235620481a(10) =5715989043a(11) =153231400343

External references