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Numbers n not divisible by 10 such that the decimal representation of n^26 does not use every nonzero digit.
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%I #25 Feb 16 2025 08:32:59

%S 1,2,3,4,6,7,8,9,12,13,14,17,23,29,39,61,81,95,119,164,242,5193,9004,

%T 23432,246968,8876708,32886598,2141194665

%N Numbers n not divisible by 10 such that the decimal representation of n^26 does not use every nonzero digit.

%C Multiples of 10 are excluded because (10*n)^k uses the same nonzero digits as n^k. - Is the sequence finite?

%C Similar sequences can be defined for other positive integer exponents. 26 is the smallest exponent such that the corresponding sequence has less than 30 terms < 10^8.

%C a(29) > 10^11, if it exists. - _Chai Wah Wu_, Sep 19 2018

%H Patrick De Geest, <a href="http://www.worldofnumbers.com/ninedig1.htm">The Nine Digits Page</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Pandigital.html">Pandigital</a>

%e 5^26 = 1490116119384765625 uses every digit, so 5 is not in the sequence.

%e 6^26 = 170581728179578208256 does not use digits 3 and 4, so 6 is a term.

%o (PARI) {e=26;for(n=1,350000,if(n%10>0,v=vector(9);c=0;k=n^e;while(c<9&&k>0, g=divrem(k,10);k=g[1];if(g[2]>0&&v[g[2]]==0,v[g[2]]=1;c++));if(c<9,print1(n,","))))}

%o (Python)

%o A112258_list = [n for n in range(1,10**6) if n % 10 and len(set(str(n**26))) < 10] # _Chai Wah Wu_, May 31 2015

%Y Cf. A089081 (26th powers).

%K nonn,base,more,changed

%O 1,2

%A _Klaus Brockhaus_, Aug 30 2005

%E a(28) from _Lars Blomberg_, Sep 25 2011