a(n) = coefficient of x in (1+x)^n mod (1+x^4).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =4a(6) =0a(7) =-14a(8) =-48a(9) =-116a(10) =-232a(11) =-396a(12) =-560a(13) =-560a(14) =0a(15) =1912a(16) =6528a(17) =15760a(18) =31520a(19) =53808a(20) =76096a(21) =76096a(22) =0a(23) =-259808a(24) =-887040a(25) =-2141504a(26) =-4283008a(27) =-7311552a(28) =-10340096a(29) =-10340096