G.f.: A(x) = exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n,k)^2 * x^k*(1-x)^k ).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =9a(6) =16a(7) =30a(8) =57a(9) =110a(10) =216a(11) =428a(12) =857a(13) =1730a(14) =3516a(15) =7191a(16) =14785a(17) =30544a(18) =63370a(19) =131976a(20) =275811a(21) =578219a(22) =1215680a(23) =2562652a(24) =5415163a(25) =11468455a(26) =24338744a(27) =51752029a(28) =110239033a(29) =235218046