Divisibility of Elements of Pythagorean Triple by 7/Mistake
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Source Work
1997: David Wells: Curious and Interesting Numbers (2nd ed.):
- The Dictionary
- $7$
Mistake
- If $a$, $b$ are the shorter sides of a Pythagorean triangle, then $7$ divides one of $a$, $b$, $a - b$ or $a - b$.
Correction
An obvious misprint for:
- If $a$, $b$ are the shorter sides of a Pythagorean triangle, then $7$ divides one of $a$, $b$, $a - b$ or $a + b$.
It can also be argued that it ought to say:
- ... then $7$ divides at least one of ...
Interestingly and oddly, this is correct in the first edition of Curious and Interesting Numbers of $1986$.
Sources
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $7$