Riordan array (1, x*g(x)) where g(x) is g.f. of double factorials A001147.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =1a(5) =1a(6) =0a(7) =3a(8) =2a(9) =1a(10) =0a(11) =15a(12) =7a(13) =3a(14) =1a(15) =0a(16) =105a(17) =36a(18) =12a(19) =4a(20) =1a(21) =0a(22) =945a(23) =249a(24) =64a(25) =18a(26) =5a(27) =1a(28) =0a(29) =10395