T(n, m) = (n+m+1)!*m!/(n+1)! + (2*n-m+1)!*(n-m)!/(n+1)! - (2*n+1)!/(n+1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =-32a(5) =1a(6) =1a(7) =-1195a(8) =-1195a(9) =1a(10) =1a(11) =-70554a(12) =-72408a(13) =-70554a(14) =1a(15) =1a(16) =-6531833a(17) =-6649664a(18) =-6649664a(19) =-6531833a(20) =1a(21) =1a(22) =-878169592a(23) =-889384176a(24) =-889565760a(25) =-889384176a(26) =-878169592a(27) =1a(28) =1a(29) =-161902540791