Determine all possible value(s) of a 15-digit base ten positive integer N which is constituted entirely by the digits 2 and 3, such that N is divisible by the base ten repunit R₇.

R[n_]:=(10^n-1)/9;
tps=Tuples[{2,3},15];
r7=R[7];
For[i=1,i„TLength[tps],++i,
n=FromDigits[tps[[i]]];
If[Mod[n,r7]ƒú0,Print[n," = ",n/r7," * ",r7];];
];

gives only 1 solution

233333323333332 = 210000012 * 1111111

Posted by Daniel on 2010-01-07 12:53:17