Expansion of 1/(2*sqrt(1-2*x-3*x^2) - 1).

Terms

a(0) =1a(1) =2a(2) =8a(3) =28a(4) =104a(5) =384a(6) =1428a(7) =5316a(8) =19820a(9) =73948a(10) =276044a(11) =1030796a(12) =3850048a(13) =14382248a(14) =53732172a(15) =200759004a(16) =750134520a(17) =2802980640a(18) =10474015164a(19) =39139487292a(20) =146259311592a(21) =546558514368