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A346674 Nonnegative numbers k such that MD5(k interpreted as a string) contains only decimal digits.

%I A346674 #19 Dec 15 2024 11:41:26
%S A346674 1518375,6637317,16781059,20274157,20680348,22080638,24026537,
%T A346674 25394302,26059015,28926467,40459791,42057668,42390227,42943634,
%U A346674 43983547,47788382,49974597,51201829,59344568,63236613,63341298,70557689,74946923,76642382,77213479,77641296
%N A346674 Nonnegative numbers k such that MD5(k interpreted as a string) contains only decimal digits.
%C A346674 See A234849 for more information about MD5.
%C A346674 This sequence is probably infinite, because MD5 returns a fixed-length output, but we don't know if outputs containing only decimal digits appear infinitely many times. Even if this is the case, it would not be enough, as we would not know if this holds when we consider the input as a number (interpreted as a string).
%H A346674 Michael S. Branicky, <a href="/A346674/b346674.txt">Table of n, a(n) for n = 1..10000</a>
%H A346674 Wikipedia, <a href="https://en.wikipedia.org/wiki/MD5">MD5</a>
%e A346674 a(1) = 1518375, because 1518375 is the smallest k >= 0 such that MD5(k) contains only decimal digits: MD5("1518375") = "93240121540327474319550261818423".
%t A346674 Monitor[Do[If[!StringContainsQ[Hash[ToString@k,"MD5","HexString"],Alphabet[]],Print@k],{k,10^9}],k] (* _Giorgos Kalogeropoulos_, Jul 28 2021 *)
%o A346674 (Python)
%o A346674 from hashlib import md5
%o A346674 i=0
%o A346674 while True:
%o A346674     m = md5()
%o A346674     m.update(str(i).encode('utf-8'))
%o A346674     result = m.hexdigest()
%o A346674     if result.isdecimal():
%o A346674         print(i)
%o A346674     i+=1
%Y A346674 Cf. A234849.
%K A346674 easy,nonn,base
%O A346674 1,1
%A A346674 _Eder Vanzei_, Jul 28 2021