E.g.f.: Product_{k>=1} (1 + x^k)^cos(x).

Terms

a(0) =1a(1) =1a(2) =2a(3) =9a(4) =30a(5) =195a(6) =1545a(7) =12474a(8) =95564a(9) =1199397a(10) =14287845a(11) =167518846a(12) =2341450386a(13) =34489552331a(14) =540927170147