Composite numbers with all divisors congruent to 1 mod 10.

Terms

a(0) =121a(1) =341a(2) =451a(3) =671a(4) =781a(5) =961a(6) =1111a(7) =1271a(8) =1331a(9) =1441a(10) =1661a(11) =1681a(12) =1891a(13) =1991a(14) =2101a(15) =2201a(16) =2321a(17) =2501a(18) =2651a(19) =2761a(20) =2911a(21) =2981a(22) =3091a(23) =3131a(24) =3421a(25) =3641a(26) =3721a(27) =3751a(28) =4061a(29) =4141