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%I #22 Mar 12 2024 23:02:05
%S 0,7,13,15,21,26,31,40,42,43,57,62,63,73,80,85,86,91,93,111,114,121,
%T 124,127,129,133,146,156,157,170,171,172,182,183,211,215,219,222,228,
%U 241,242,255,259,266,273,285,292,307,312,314,333,341,342,343,364,365,366
%N Numbers that are repdigits with length > 2 in some base.
%C Definition requires "length > 2" because all numbers n > 2 are trivially represented as "11" in base n-1.
%C 0 included at the suggestion of _Franklin T. Adams-Watters_ (and others) as 0 = 000 in any base.
%H Vojtech Strnad, <a href="/A167782/b167782.txt">Table of n, a(n) for n = 1..10000</a>
%H Wolfram Demonstrations Project, <a href="http://demonstrations.wolfram.com/MixedRadixNumberRepresentations/">Mixed Radix Number Representations</a> [From _Daniel Forgues_, Nov 13 2009]
%e 26 is a term because 26_10 = 222_3.
%o (PARI) digits(n,b) = if(n<b, [n], concat(digits(floor(n/b),b),n%b))
%o is_repdigit(d) = {local(a,r);r=1;a=d[1];for(i=2,matsize(d)[2],if(a!=d[i],r=0));r}
%o for(n=1,1200,b=2;while(n>=b^2+b+1,d=digits(n,b);if(is_repdigit(d),print(n," = ",d," base ",b));b++)) \\ _Michael B. Porter_
%Y Cf. A010785 (Repdigits (base 10)).
%Y Cf. A167783 (Numbers that are repdigits with length > 2 in more than one base).
%Y Cf. A053696 (Numbers which are repunits in some base).
%Y Cf. A158235 (Numbers n whose square can be represented as a repdigit number in some base < n).
%K nonn,base
%O 1,2
%A _Andrew Weimholt_, Nov 12 2009
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