Floor(n^2*exp(n)).

Terms

a(0) =2a(1) =29a(2) =180a(3) =873a(4) =3710a(5) =14523a(6) =53735a(7) =190781a(8) =656349a(9) =2202646a(10) =7244771a(11) =23436689a(12) =74767863a(13) =235710439a(14) =735528908a(15) =2274844293a(16) =6980781345a(17) =21273830000a(18) =64432110647a(19) =194066078163a(20) =581597738907