Numbers k such that (28*10^k - 31)/3 is prime.

Terms

a(0) =1a(1) =3a(2) =4a(3) =13a(4) =15a(5) =24a(6) =28a(7) =48a(8) =233a(9) =558a(10) =621a(11) =1498a(12) =1810a(13) =2788a(14) =3532a(15) =3987a(16) =4791a(17) =7972a(18) =12221a(19) =13714a(20) =15940a(21) =41759a(22) =46956a(23) =47827a(24) =51651a(25) =102142