Every digit of prime and its index contains a loop (only digits 0,4,6,8,9 in prime and its index).

Terms

a(0) =409a(1) =4409a(2) =4999a(3) =6869a(4) =44699a(5) =44909a(6) =46499a(7) =48409a(8) =64849a(9) =66889a(10) =68449a(11) =68909a(12) =86969a(13) =89689a(14) =98869a(15) =98899a(16) =480499a(17) =488689a(18) =490499a(19) =609809a(20) =806609a(21) =806999a(22) =866969a(23) =868669a(24) =868849a(25) =869489a(26) =869849a(27) =869899a(28) =869909a(29) =880949