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 A199349 #23 Jul 14 2025 17:28:31
%S A199349 3,43,349,433,439,443,449,499,3343,3433,3449,3499,3943,4339,4349,4493,
%T A199349 4933,4943,4993,4999,9343,9349,9433,9439,9949,33343,33349,33493,34439,
%U A199349 34499,34939,34949,39343,39439,39443,39499,43399,43499,43933,43943,44449,44939,49333,49339,49393,49433,49499,49939,49943,49993
%N A199349 Primes having only {3, 4, 9} as digits.
%C A199349 A020461 and A020466 are subsequences. - _Vincenzo Librandi_, Jul 30 2015
%H A199349 Alois P. Heinz, <a href="/A199349/b199349.txt">Table of n, a(n) for n = 1..10000</a>
%H A199349 <a href="/index/Pri#PrimesWithDigits">Index to entries about primes with digits in a given set</a>.
%t A199349 Select[Prime[Range[2 10^4]], Complement[IntegerDigits[#], {3, 4, 9}]=={} &] (* _Vincenzo Librandi_, Jul 30 2015 *)
%t A199349 Select[Flatten[Table[FromDigits/@Tuples[{3,4,9},n],{n,5}]],PrimeQ] (* _Harvey P. Dale_, May 02 2023 *)
%o A199349 (PARI) a(n, list=0, L=[3,4,9], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vecextract(L,v)*u) || next; reqpal && !isprime(A004086(t)) && next; list && print1(t", "); n--||return(t)))}
%o A199349 (Magma) [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [3, 4, 9]]; // _Vincenzo Librandi_, Jul 30 2015
%Y A199349 Cf. Primes that contain only the digits (3,4,k): A199340 (k=0), A199341 (k=1), A199342 (k=2), A199345 (k=5), A199346 (k=6), A199347 (k=7), A199348 (k=8).
%Y A199349 Cf. A020449 - A020472, A199325 - A199329.
%K A199349 nonn,base
%O A199349 1,1
%A A199349 _M. F. Hasler_, Nov 05 2011