a(n) = 2*a(n-1) + a(n-2) + n^2 for n > 1, with a(0) = 0, a(1) = 1.

Terms

a(0) =0a(1) =1a(2) =6a(3) =22a(4) =66a(5) =179a(6) =460a(7) =1148a(8) =2820a(9) =6869a(10) =16658a(11) =40306a(12) =97414a(13) =235303a(14) =568216a(15) =1371960a(16) =3312392a(17) =7997033a(18) =19306782a(19) =46610958a(20) =112529098a(21) =271669595a(22) =655868772a(23) =1583407668a(24) =3822684684a(25) =9228777661a(26) =22280240682a(27) =53789259754a(28) =129858760974a(29) =313506782543