Triplet in Arithmetic Sequence with equal Sigma
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Theorem
The smallest triple of integers in arithmetic sequence which have the same $\sigma$ (sigma) value is:
- $\map \sigma {267} = \map \sigma {295} = \map \sigma {323} = 360$
Proof
We have that:
\(\ds 295 - 267\) | \(=\) | \(\ds 28\) | ||||||||||||
\(\ds 323 - 295\) | \(=\) | \(\ds 28\) |
demonstrating that $267, 295, 323$ are in arithmetic sequence with common difference $28$.
Then:
\(\ds \map \sigma {267}\) | \(=\) | \(\ds 360\) | $\sigma$ of $267$ | |||||||||||
\(\ds \map \sigma {295}\) | \(=\) | \(\ds 360\) | $\sigma$ of $295$ | |||||||||||
\(\ds \map \sigma {323}\) | \(=\) | \(\ds 360\) | $\sigma$ of $323$ |
Sources
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $267$