This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A057628 #19 Dec 31 2023 10:31:43
%S A057628 11,31,53,131,149,223,283,311,313,331,397,463,641,691,937,941,1439,
%T A057628 1511,1741,1871,1949,1993,1999,2111,2447,2939,3163,3391,3433,3499,
%U A057628 3559,3593,3659,3911,3931,5227,5399,5923,6163,6269,6653,6719,7177,7741,8389
%N A057628 Primes such that replacing each digit d with d copies of the digit d produces a prime. Zeros are not allowed.
%C A057628 "Replacing each digit d with d copies of the digit d" is the function A048376. Therefore this is the largest subset of A038618 stable under the map A048376.
%e A057628 E.g. 641 becomes 66666644441 which is also prime.
%t A057628 Select[Prime[Range[1500]],PrimeQ[FromDigits[Flatten[Table[#,{#}]&/@ IntegerDigits[#]]]]&&DigitCount[#,10,0]==0&] (* _Harvey P. Dale_, Mar 27 2011 *)
%o A057628 (PARI) is_A057628(n)={vecmin(digits(n)) && is_A057630(n)} \\ _M. F. Hasler_, Jan 23 2013
%Y A057628 Cf. A038618, A048376, A057630.
%K A057628 nonn,base,nice,easy
%O A057628 1,1
%A A057628 _G. L. Honaker, Jr._, Oct 10 2000
%E A057628 More terms from _Patrick De Geest_, Oct 15 2000.
%E A057628 Offset changed to 1, according to OEIS conventions, by _M. F. Hasler_, Jan 23 2013