a(n) = 625*n - 1.

Terms

a(0) =624a(1) =1249a(2) =1874a(3) =2499a(4) =3124a(5) =3749a(6) =4374a(7) =4999a(8) =5624a(9) =6249a(10) =6874a(11) =7499a(12) =8124a(13) =8749a(14) =9374a(15) =9999a(16) =10624a(17) =11249a(18) =11874a(19) =12499a(20) =13124a(21) =13749a(22) =14374a(23) =14999a(24) =15624a(25) =16249a(26) =16874a(27) =17499a(28) =18124a(29) =18749