Residue C(2^n,n) mod C(2^n,2).

Terms

a(0) =0a(1) =0a(2) =0a(3) =20a(4) =0a(5) =1344a(6) =0a(7) =8160a(8) =0a(9) =349184a(10) =0a(11) =1397760a(12) =0a(13) =0a(14) =306774016a(15) =268431360a(16) =0a(17) =7635468288a(18) =0a(19) =494779760640a(20) =942438088704a(21) =0a(22) =0a(24) =0a(25) =0a(26) =0a(28) =0a(30) =0a(32) =0a(34) =0