Denominators of b(n) = b(n-1)/2 + 1/(2*n), b(0)=0.

Terms

a(0) =1a(1) =2a(2) =2a(3) =12a(4) =3a(5) =15a(6) =60a(7) =840a(8) =105a(9) =630a(10) =630a(11) =13860a(12) =6930a(13) =180180a(14) =360360a(15) =144144a(16) =9009a(17) =306306a(18) =306306a(19) =11639628a(20) =14549535a(21) =14549535a(22) =58198140a(23) =2677114440a(24) =334639305a(25) =3346393050