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 A077533 #19 Feb 27 2025 19:40:01
%S A077533 3,27,33,57,72,75,222,225,237,252,255,273,327,333,357,372,375,522,525,
%T A077533 537,552,555,573,723,732,735,753,777,2223,2232,2235,2253,2277,2322,
%U A077533 2325,2337,2352,2355,2373,2523,2532,2535,2553,2577,2727,2733,2757,2772,2775
%N A077533 Multiples of 3 using only prime digits (2, 3, 5 and 7).
%H A077533 David A. Corneth, <a href="/A077533/b077533.txt">Table of n, a(n) for n = 1..10000</a>
%H A077533 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.
%t A077533 ok3Q[n_]:=And@@(MemberQ[{2,3,5,7},#]&/@IntegerDigits[n]); Select[3Range[0,1000],ok3Q] (* _Harvey P. Dale_, Mar 22 2011 *)
%t A077533 Select[Flatten[Table[FromDigits/@Tuples[{2,3,5,7},n],{n,4}]],Mod[#,3]==0&] (* _Harvey P. Dale_, Feb 27 2025 *)
%o A077533 (Python)
%o A077533 def pd(n): return set(str(n)) <= set("2357") # has only prime digits
%o A077533 def aupto(limit): return [m for m in range(0, limit+1, 3) if pd(m)]
%o A077533 print(aupto(3000)) # _Michael S. Branicky_, Mar 27 2021
%Y A077533 Cf. A008585 (multiples of 3), A046034 (prime digits).
%K A077533 base,nonn
%O A077533 1,1
%A A077533 _Amarnath Murthy_, Nov 08 2002
%E A077533 More terms from _Sascha Kurz_, Jan 03 2003