Primes with consecutive digits that differ exactly by 3.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =41a(5) =47a(6) =14741a(7) =14747a(8) =74747a(9) =1414741a(10) =1474141a(11) =7414741a(12) =4141414747a(13) =4147414147a(14) =14141414141a(15) =14141414741a(16) =14141474741a(17) =14141474747a(18) =14147414741a(19) =14147474141a(20) =14147474147a(21) =14741414747a(22) =74141414147a(23) =74141414741a(24) =74147414741a(25) =74741474741a(26) =74747414141