Expansion of 1/(x^k*(1 - x - 3*x^(k+1))) for k=3.

Terms

a(0) =1a(1) =4a(2) =7a(3) =10a(4) =13a(5) =25a(6) =46a(7) =76a(8) =115a(9) =190a(10) =328a(11) =556a(12) =901a(13) =1471a(14) =2455a(15) =4123a(16) =6826a(17) =11239a(18) =18604a(19) =30973a(20) =51451a(21) =85168a(22) =140980a(23) =233899a(24) =388252a(25) =643756a(26) =1066696a(27) =1768393a(28) =2933149a(29) =4864417