Expansion of (1 + x*c(x))/(1 - x), where c(x) is the g.f. of A000108.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =10a(5) =24a(6) =66a(7) =198a(8) =627a(9) =2057a(10) =6919a(11) =23715a(12) =82501a(13) =290513a(14) =1033413a(15) =3707853a(16) =13402698a(17) =48760368a(18) =178405158a(19) =656043858a(20) =2423307048a(21) =8987427468a(22) =33453694488a(23) =124936258128a(24) =467995871778