a(n) = 400*n - 1.

Terms

a(0) =399a(1) =799a(2) =1199a(3) =1599a(4) =1999a(5) =2399a(6) =2799a(7) =3199a(8) =3599a(9) =3999a(10) =4399a(11) =4799a(12) =5199a(13) =5599a(14) =5999a(15) =6399a(16) =6799a(17) =7199a(18) =7599a(19) =7999a(20) =8399a(21) =8799a(22) =9199a(23) =9599a(24) =9999a(25) =10399a(26) =10799a(27) =11199a(28) =11599a(29) =11999