Expansion of 1/(x^k*(1-x-3*x^(k+1))) for k=4.

Terms

a(0) =1a(1) =4a(2) =7a(3) =10a(4) =13a(5) =16a(6) =28a(7) =49a(8) =79a(9) =118a(10) =166a(11) =250a(12) =397a(13) =634a(14) =988a(15) =1486a(16) =2236a(17) =3427a(18) =5329a(19) =8293a(20) =12751a(21) =19459a(22) =29740a(23) =45727a(24) =70606a(25) =108859a(26) =167236a(27) =256456a(28) =393637a(29) =605455