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

1518375, 6637317, 16781059, 20274157, 20680348, 22080638, 24026537, 25394302, 26059015, 28926467, 40459791, 42057668, 42390227, 42943634, 43983547, 47788382, 49974597, 51201829, 59344568, 63236613, 63341298, 70557689, 74946923, 76642382, 77213479, 77641296

Offset: 1

Author

Eder Vanzei, Jul 28 2021

Keywords

• easy
• nonn
• base

Comments

See A234849 for more information about MD5.

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).

Examples

			a(1) = 1518375, because 1518375 is the smallest k >= 0 such that MD5(k) contains only decimal digits: MD5("1518375") = "93240121540327474319550261818423".
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000
• Wikipedia, MD5

Crossrefs

Cf. A234849.

Programs

Mathematica

Monitor[Do[If[!StringContainsQ[Hash[ToString@k,"MD5","HexString"],Alphabet[]],Print@k],{k,10^9}],k] (* Giorgos Kalogeropoulos, Jul 28 2021 *)

Python

from hashlib import md5
i=0
while True:
    m = md5()
    m.update(str(i).encode('utf-8'))
    result = m.hexdigest()
    if result.isdecimal():
        print(i)
    i+=1