a(n) = 5^n-prevprime(5^n).

Terms

a(0) =2a(1) =2a(2) =12a(3) =6a(4) =4a(5) =6a(6) =4a(7) =44a(8) =16a(9) =6a(10) =12a(11) =12a(12) =52a(13) =2a(14) =4a(15) =62a(16) =16a(17) =102a(18) =16a(19) =26a(20) =54a(21) =54a(22) =36a(23) =38a(24) =64a(25) =2a(26) =12a(27) =42a(28) =16a(29) =102