1000-gonal numbers: a(n) = n*(499*n - 498).

Terms

a(0) =0a(1) =1a(2) =1000a(3) =2997a(4) =5992a(5) =9985a(6) =14976a(7) =20965a(8) =27952a(9) =35937a(10) =44920a(11) =54901a(12) =65880a(13) =77857a(14) =90832a(15) =104805a(16) =119776a(17) =135745a(18) =152712a(19) =170677a(20) =189640a(21) =209601a(22) =230560a(23) =252517a(24) =275472a(25) =299425a(26) =324376a(27) =350325a(28) =377272a(29) =405217