Expansion of g.f. (1-x-2*x^2-x^3+x^4)/((x-1)^3*(6*x^2+2*x-1)).

Terms

a(0) =1a(1) =4a(2) =15a(3) =51a(4) =183a(5) =655a(6) =2381a(7) =8653a(8) =31539a(9) =114927a(10) =419001a(11) =1527457a(12) =5568791a(13) =20302171a(14) =74016909a(15) =269846637a(16) =983794491a(17) =3586668535a(18) =13076103713a(19) =47672218297a(20) =173801058495a(21) =633635426355