Expansion of 1/sqrt(1-4x+20x^2).

Terms

a(0) =1a(1) =2a(2) =-4a(3) =-40a(4) =-80a(5) =352a(6) =2624a(7) =3712a(8) =-32000a(9) =-186880a(10) =-134144a(11) =2885632a(12) =13520896a(13) =-1269760a(14) =-256000000a(15) =-966164480a(16) =1056112640a(17) =22286827520a(18) =66722201600a(19) =-162411315200