p-INVERT of the positive integers, where p(S) = (1 - S)^4.

Terms

a(0) =4a(1) =18a(2) =72a(3) =271a(4) =976a(5) =3398a(6) =11516a(7) =38179a(8) =124272a(9) =398248a(10) =1259240a(11) =3935420a(12) =12173440a(13) =37314700a(14) =113452128a(15) =342426657a(16) =1026711724a(17) =3059968146a(18) =9069834488a(19) =26748151221a(20) =78518859336a(21) =229505772002a(22) =668173273988