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

Terms

a(0) =1a(1) =3a(2) =7a(3) =17a(4) =40a(5) =92a(6) =208a(7) =464a(8) =1024a(9) =2240a(10) =4864a(11) =10496a(12) =22528a(13) =48128a(14) =102400a(15) =217088a(16) =458752a(17) =966656a(18) =2031616a(19) =4259840a(20) =8912896a(21) =18612224a(22) =38797312a(23) =80740352a(24) =167772160a(25) =348127232a(26) =721420288a(27) =1493172224a(28) =3087007744a(29) =6375342080