a(n) = C(n+11, 11)*(n+6)*(-1)^(n+1)*512/3.

Terms

a(0) =-1024a(1) =14336a(2) =-106496a(3) =559104a(4) =-2329600a(5) =8200192a(6) =-25346048a(7) =70606848a(8) =-180590592a(9) =429977600a(10) =-963149824a(11) =2046693376a(12) =-4153583616a(13) =8094162944a(14) =-15214592000a(15) =27690557440a(16) =-48952949760a(17) =84293314560a(18) =-141710499840a(19) =233076480000