a(n) is the decimal expansion of 7nn7.

Terms

a(0) =7007a(1) =7117a(2) =7227a(3) =7337a(4) =7447a(5) =7557a(6) =7667a(7) =7777a(8) =7887a(9) =7997a(10) =710107a(11) =711117a(12) =712127a(13) =713137a(14) =714147a(15) =715157a(16) =716167a(17) =717177a(18) =718187a(19) =719197a(20) =720207a(21) =721217a(22) =722227a(23) =723237a(24) =724247a(25) =725257a(26) =726267a(27) =727277a(28) =728287a(29) =729297