Coefficients of polynomials ( (1 -x +sqrt(x))^n + (1 -x -sqrt(x))^n )/2.

Terms

a(0) =1a(1) =1a(2) =-1a(3) =1a(4) =-1a(5) =1a(6) =1a(7) =0a(8) =0a(9) =-1a(10) =1a(11) =2a(12) =-5a(13) =2a(14) =1a(15) =1a(16) =5a(17) =-15a(18) =15a(19) =-5a(20) =-1a(21) =1a(22) =9a(23) =-30a(24) =41a(25) =-30a(26) =9a(27) =1a(28) =1a(29) =14