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Owlet puzzle #36

Released Monday, August 10, 2026 UTC

1618
the answer for puzzle #36

The five clues

  1. A four-digit even number under 2000.
  2. Its digits echo an irrational constant.
  3. The first four digits of the golden ratio φ = (1+√5)/2 ≈ 1.6180339…
  4. The golden ratio, written without a decimal point.
  5. Immediately before 1619, itself a prime.

Backstory

1618 is the golden ratio φ ≈ 1.6180339887, with the decimal removed. φ² = φ + 1, making it the positive root of x² = x + 1. Appears in sunflower spirals, Fibonacci ratios, and pentagram geometry — though its role in the Parthenon is disputed by scholars.

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