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

Terms

a(0) =1a(1) =4a(2) =17a(3) =71a(4) =297a(5) =1242a(6) =5194a(7) =21721a(8) =90836a(9) =379871a(10) =1588599a(11) =6643431a(12) =27782452a(13) =116184640a(14) =485877581a(15) =2031912512a(16) =8497342989a(17) =35535406887a(18) =148607058025a(19) =621466295998