Expansion of 2-sqrt(1-4*x-4*x^2-4*x^3).

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =28a(5) =96a(6) =354a(7) =1372a(8) =5512a(9) =22740a(10) =95768a(11) =410016a(12) =1779210a(13) =7807724a(14) =34589432a(15) =154488460a(16) =694883528a(17) =3144917888a(18) =14311109396a(19) =65439770904a(20) =300534169744