Numbers k such that (25*10^k - 241)/9 is prime.

Terms

a(0) =2a(1) =4a(2) =5a(3) =8a(4) =20a(5) =35a(6) =80a(7) =131a(8) =169a(9) =262a(10) =364a(11) =484a(12) =580a(13) =692a(14) =1687a(15) =1834a(16) =3476a(17) =3950a(18) =5963a(19) =6329a(20) =13339a(21) =18617a(22) =72703a(23) =103360