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 A385784 #8 Jul 13 2025 11:04:53
%S A385784 2,7,47,227,277,727,2447,2477,2777,4447,7247,7477,7727,22247,22277,
%T A385784 22447,22727,22777,24247,27277,27427,42227,42727,44777,47777,72227,
%U A385784 72277,72727,74747,77447,77477,77747,222247,242227,242447,242747,244247,244747,272227
%N A385784 Primes having only {2, 4, 7} as digits.
%H A385784 Jason Bard, <a href="/A385784/b385784.txt">Table of n, a(n) for n = 1..10000</a>
%H A385784 <a href="/index/Pri#PrimesWithDigits">Index to entries for primes with digits in a given set</a>
%t A385784 Flatten[Table[Select[FromDigits /@ Tuples[{2, 4, 7}, n], PrimeQ], {n, 7}]]
%o A385784 (Magma) [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [2, 4, 7]];
%o A385784 (Python) print(list(islice(primes_with("247"), 41))) # uses function/imports in A385776
%o A385784 (PARI) primes_with(, 1, [2, 4, 7]) \\ uses function in A385776
%Y A385784 Supersequence of A020459, A020465.
%Y A385784 Cf. A000040, A030432, A385776.
%K A385784 nonn,base,easy
%O A385784 1,1
%A A385784 _Jason Bard_, Jul 13 2025