Numbers k such that 49*10^k + 1 is prime.

Terms

a(0) =1a(1) =4a(2) =5a(3) =7a(4) =9a(5) =10a(6) =18a(7) =19a(8) =34a(9) =52a(10) =71a(11) =180a(12) =238a(13) =331a(14) =370a(15) =576a(16) =925a(17) =994a(18) =1075a(19) =1841a(20) =2460a(21) =2857a(22) =6007a(23) =6193a(24) =10836a(25) =18732a(26) =58708a(27) =72861