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

Terms

a(0) =1a(1) =5a(2) =21a(3) =83a(4) =319a(5) =1209a(6) =4549a(7) =17051a(8) =63783a(9) =238337a(10) =890077a(11) =3322995a(12) =12403951a(13) =46296905a(14) =172791861a(15) =644886923a(16) =2406788599a(17) =8982333009a(18) =33522674509a(19) =125108627171a(20) =466912358463