Numbers k such that (16*10^k - 31)/3 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =15a(5) =20a(6) =24a(7) =32a(8) =38a(9) =40a(10) =63a(11) =93a(12) =104a(13) =194a(14) =208a(15) =514a(16) =535a(17) =600a(18) =928a(19) =1300a(20) =1485a(21) =1780a(22) =2058a(23) =3060a(24) =3356a(25) =3721a(26) =6662a(27) =11552a(28) =15482a(29) =23000