Expansion of (1-2*x^2)/((1-2*x)*(1+x-x^2)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =7a(5) =12a(6) =27a(7) =49a(8) =106a(9) =199a(10) =419a(11) =804a(12) =1663a(13) =3237a(14) =6618a(15) =13003a(16) =26383a(17) =52156a(18) =105299a(19) =209001a(20) =420586a(21) =836991a(22) =1680747a(23) =3350548a(24) =6718807a(25) =13408957a(26) =26864282a(27) =53653539a(28) =107428471a(29) =214660524