MathDB

Mutliplying by 9 reverses digits [ILL 1977]

Source:

January 11, 2011

inductionnumber theory unsolvednumber theory

Problem Statement

Find all numbers

N=\overline{a_1a_2\ldots a_n}

for which

9\times \overline{a_1a_2\ldots a_n}=\overline{a_n\ldots a_2a_1}

such that at most one of the digits

a_1,a_2,\ldots ,a_n

is zero.