- John Grantham
- Witold Jarnicki
- Jon Rickert
- Stan Wagon
The American Mathematical Monthly (2012) (to appear)
We investigate the problem of nding integers k such that ap- pending any number of copies of the base-ten digit d to k yields a composite number. In particular, we prove that there exist innitely many integers co- prime to all digits such that repeatedly appending any digit yields a composite number.
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