a(n) = n*a(n-3) + a(n-4) for n >= 4.

Terms

a(0) =0a(1) =1a(2) =0a(3) =0a(4) =4a(5) =1a(6) =0a(7) =28a(8) =12a(9) =1a(10) =280a(11) =160a(12) =24a(13) =3641a(14) =2520a(15) =520a(16) =58280a(17) =46481a(18) =11880a(19) =1107840a(20) =987900a(21) =295961a(22) =24384360a(23) =23829540a(24) =8090964a(25) =609904961a(26) =643952400a(27) =242285568a(28) =17085429872a(29) =19284524561