E.g.f.: Product_{m>0} (1 + x^(2*m-1)).

Terms

a(0) =1a(1) =1a(2) =0a(3) =6a(4) =24a(5) =120a(6) =720a(7) =5040a(8) =80640a(9) =725760a(10) =7257600a(11) =79833600a(12) =1437004800a(13) =18681062400a(14) =261534873600