olymmath

ISL 2023 N1

Determine all positive, composite integers nn that satisfy the following property: if the positive divisors of nn are 1=d1<d2<⋯<dk=n1=d_{1}<d_{2}<\cdots<d_{k}=n, then did_{i} divides di+1+di+2d_{i+1}+d_{i+2} for every 1⩽i⩽k−21 \leqslant i \leqslant k-2. (Colombia)

Official text Transcription from NuminaMath olympiads, checked word for word against the official paper. Quoted with source.

Official text: IMO 2023 Shortlist booklet, page 11.

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n=p^{r}

Solutions

Official solution Solution 1 by the IMO Problem Selection Committee

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