“In mathematics, the look-and-say sequence is the sequence of integers beginning as follows:
1, 11, 21, 1211, 111221, 312211, 13112221, 1113213211, 31131211131221, … (sequence A005150 in the OEIS).”
“To generate a member of the sequence from the previous member, read off the digits of the previous member, counting the number of digits in groups of the same digit. For example:
- 1 is read off as “one 1” or 11.
- 11 is read off as “two 1s” or 21.
- 21 is read off as “one 2, one 1” or 1211.
- 1211 is read off as “one 1, one 2, two 1s” or 111221.
- 111221 is read off as “three 1s, two 2s, one 1” or 312211.”
“The look-and-say sequence was analyzed by John Conway[1] after he was introduced to it by one of his students at a party”
“Conway’s cosmological theorem asserts that every sequence eventually splits (“decays”) into a sequence of “atomic elements”, which are finite subsequences that never again interact with their neighbors. There are 92 elements containing the digits 1, 2, and 3 only, which John Conway named after the 92 naturally-occurring chemical elements up to uranium, calling the sequence audioactive. There are also two “transuranic” elements (Np and Pu) for each digit other than 1, 2, and 3”