Owlet puzzle #89
Released Friday, October 2, 2026 UTC
144
the answer for puzzle #89
The five clues
- A three-digit perfect square divisible by 12.
- A three-digit even Fibonacci number.
- A perfect square that is also a Fibonacci number.
- By Bugeaud–Mignotte–Siksek's 2006 result, the only Fibonacci squares are 0, 1, and 144.
- A dozen dozens — also called a 'gross'.
Backstory
144 = 12² = F₁₂ is the only Fibonacci number greater than 1 that is also a perfect square — proved by John H. E. Cohn in 1964. Called a 'gross' in commerce, and equal to a dozen dozens. Its square root 12 is also F₁₂'s index, a rare index-value coincidence.
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