# 471 series/series.32.p

## Description

This article is from the Puzzles FAQ,
by Chris Cole chris@questrel.questrel.com and Matthew Daly
mwdaly@pobox.com with numerous contributions by others.

# 471 series/series.32.p

0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1

series/series.32.s

0 -> 1 01 -> 10 0110 -> 1001 01101001 -> 10010110

Recursively append the inverse.

This sequence is known as the Morse-Thue sequence. It can be defined

non-recursively as the nth term is the mod 2 count of 1s in n written

in binary:

0->0 1->1 10->1 11->0 100->1 101->0 110->0 111->1 etc.

Reference:

Dekking, et. al., "Folds! I,II,III"

The Mathematical Intelligencer, v4,#3,#4,#4.

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