Numbers k such that 4*10^k - 63 is prime.

Terms

a(0) =2a(1) =4a(2) =5a(3) =8a(4) =9a(5) =15a(6) =19a(7) =25a(8) =26a(9) =137a(10) =141a(11) =257a(12) =399a(13) =508a(14) =524a(15) =607a(16) =709a(17) =953a(18) =989a(19) =2484a(20) =3196a(21) =4538a(22) =6448a(23) =35401a(24) =36106a(25) =51530a(26) =79327a(27) =109316a(28) =171891a(29) =184004