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Look and Say Sequence

Conway's look-and-say sequence generator.

Look and say sequence
  • 1.1(1 digits)
  • 2.11(2 digits)
  • 3.21(2 digits)
  • 4.1211(4 digits)
  • 5.111221(6 digits)
  • 6.312211(6 digits)
  • 7.13112221(8 digits)
  • 8.1113213211(10 digits)

How it reads

Read each row aloud as a count of digits: "1" → "one one" → "11" → "two ones" → "21" → "one two, one one" → "1211"... and so on.

John Conway proved the length grows by a factor of 1.303577... per step (Conway's constant).

Conway's look-and-say sequence. Famous fact: digits never exceed 3, and the limiting growth rate (Conway's constant) is the only positive real root of a degree-71 polynomial Conway found in 1986.

About

Pick a seed and number of iterations. Each row reads the previous row aloud (1 → 11 → 21 → 1211 → 111221). Famous mathematical sequence by John Conway with surprising properties.

How to use

  1. Pick a seed and iterations.

FAQ

Why does it always start small?+

Conway proved the sequence grows by a factor of 1.303577... per step. Start with 1 and after 30 steps you're around 5,800 digits.