a(0) = 1 and a(n) = A180000(n)*a(floor(n/2))^2 for n > 0.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =3a(8) =48a(9) =16a(10) =40a(11) =40a(12) =270a(13) =270a(14) =945a(15) =63a(16) =129024a(17) =129024a(18) =64512a(19) =64512a(20) =2016000a(21) =96000a(22) =528000a(23) =528000a(24) =144342000a(25) =28868400a(26) =187644600a(27) =20849400a(28) =1787836050a(29) =1787836050