G.f.: A(x) = exp( Sum_{n>=1,k>=0} CATALAN(n,k)^2*x^(n+k)/n ), where CATALAN(n,k) = n*C(n+2*k-1,k)/(n+k) is the coefficient of x^k in C(x)^n and C(x) is the g.f. of the Catalan numbers.
A183070
G.f.: A(x) = exp( Sum_{n>=1,k>=0} CATALAN(n,k)^2*x^(n+k)/n ), where CATALAN(n,k) = n*C(n+2*k-1,k)/(n+k) is the coefficient of x^k in C(x)^n and C(x) is the g.f. of the Catalan numbers.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =8a(4) =49a(5) =380a(6) =3400a(7) =33469a(8) =352763a(9) =3914105a(10) =45203847a(11) =539095203a(12) =6600723606a(13) =82616454685
External references
- oeis: A183070