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 A217039 #29 Jul 20 2025 18:00:15
%S A217039 5,7,47,457,547,557,577,757,4447,4457,4547,5477,5557,7457,7477,7547,
%T A217039 7577,7757,44777,45557,45757,47777,54547,54577,55457,55547,57457,
%U A217039 57557,74747,75557,75577,77447,77477,77557,77747,444547,444557,445447,445477,445747,447757
%N A217039 Primes having only {4, 5, 7} as digits.
%C A217039 These are the primes in A214584. Primes whose numerals are all written (san serif) with at least one right or acute angle.
%H A217039 Jason Bard, <a href="/A217039/b217039.txt">Table of n, a(n) for n = 1..10000</a>
%H A217039 <a href="/index/Pri#PrimesWithDigits">Index to entries for primes with digits in a given set</a>
%F A217039 A000040 INTERSECTION A214584.
%t A217039 Select[Flatten[Table[FromDigits/@Tuples[{4,5,7},n],{n,6}]],PrimeQ] (* _Bruno Berselli_, Sep 25 2012 *)
%o A217039 (Magma) [p: p in PrimesUpTo(450000) | Intseq(p) subset [4,5,7]]; // _Bruno Berselli_, Sep 25 2012
%o A217039 (PARI) A217039(n=50,show=0,L=[4,5,7])={for(d=1,1e9, my(t, u=vector(d,i,10^(d-i))~); forvec(v=vector(d,i,[if(i==d&&d>1,3/*must end in 7*/,1), #L]), ispseudoprime(t=vecextract(L, v)*u)||next; show&&print1(t", "); n--||return(t)))} \\ Syntax updated for newer PARI versions by _M. F. Hasler_, Jul 25 2015
%Y A217039 Cf. A079651, A079652, A214584.
%Y A217039 Cf. A036953, A260044, A260267 - A260271, A199325 - A199329, A061247, A199340 - A199349.
%K A217039 nonn,base,easy
%O A217039 1,1
%A A217039 _Jonathan Vos Post_, Sep 24 2012