1-sequence of reduction of pentagonal numbers sequence by x^2 -> x+1.

Terms

a(0) =0a(1) =5a(2) =17a(3) =61a(4) =166a(5) =421a(6) =981a(7) =2177a(8) =4634a(9) =9564a(10) =19244a(11) =37934a(12) =73502a(13) =140373a(14) =264783a(15) =494143a(16) =913618a(17) =1675387a(18) =3050075a(19) =5516865a(20) =9920880a(21) =17747270a(22) =31597272a(23) =56013036a(24) =98903436a(25) =174003461a(26) =305107901a(27) =533345617a(28) =929655934a(29) =1616151649