Expansion of g.f. (1-6*x+7*x^2)/(1-7*x+11*x^2-x^3).

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =45a(5) =197a(6) =895a(7) =4143a(8) =19353a(9) =90793a(10) =426811a(11) =2008307a(12) =9454021a(13) =44513581a(14) =209609143a(15) =987068631a(16) =4648293425a(17) =21889908177a(18) =103085198195a(19) =485455690843