a(n) = 15780962*n^2 - 25943924*n + 10662963.

Terms

a(0) =500001a(1) =21898963a(2) =74859849a(3) =159382659a(4) =275467393a(5) =423114051a(6) =602322633a(7) =813093139a(8) =1055425569a(9) =1329319923a(10) =1634776201a(11) =1971794403a(12) =2340374529a(13) =2740516579a(14) =3172220553a(15) =3635486451a(16) =4130314273a(17) =4656704019a(18) =5214655689a(19) =5804169283