#1128 · Number Theory · Divisibility
Divisibility by $r+1$ for symmetric digits
In base , suppose a number has an even number of digits and each pair of digits equidistant from the ends are equal. Prove that the number is divisible by .
H. S. Hall & S. R. Knight, Higher Algebra (1891) · Ch. VII. Scales of Notation, Examples VII.b, No. 36
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