E.g.f. (1-x)/(1-x-x^5).

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =120a(6) =720a(7) =5040a(8) =40320a(9) =362880a(10) =7257600a(11) =119750400a(12) =1916006400a(13) =31135104000a(14) =523069747200