G.f. satisfies A(x) = exp( Sum_{n>=1} (A(x^n) + A(-x^n))/2 * x^n/n ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =4a(6) =5a(7) =10a(8) =12a(9) =25a(10) =33a(11) =68a(12) =91a(13) =190a(14) =264a(15) =555a(16) =780a(17) =1649a(18) =2365a(19) =5021a(20) =7274a(21) =15518a(22) =22727a(23) =48646a(24) =71784a(25) =154162a(26) =229094a(27) =493346a(28) =737215a(29) =1591518