[n/2]!*[(n+1)/2]!*C([n/2],5)*C([(n+1)/2],5).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =14400a(10) =518400a(11) =18662400a(12) =457228800a(13) =11202105600a(14) =238978252800