Numbers n, not relatively prime to 10, such that the decimal form of the period of 1/n is prime.

Terms

a(0) =12a(1) =18a(2) =30a(3) =36a(4) =45a(5) =48a(6) =75a(7) =120a(8) =180a(9) =192a(10) =198a(11) =270a(12) =288a(13) =300a(14) =330a(15) =360a(16) =450a(17) =480a(18) =495a(19) =750a(20) =768a(21) =1152a(22) =1200a(23) =1584a(24) =1800a(25) =1875a(26) =1920a(27) =1980a(28) =1998a(29) =2304