OFFSET
0,6
COMMENTS
This is a table read by rows of length 4. Every row is formed from the previous one by the circular Pascal triangle-like rule: a, b, c, d -> d+a, a+b, b+c, c+d. Consider a labeled binary tree such that the root has label 0 and every node labeled k has children labeled k and (k+1) mod 4; the n-th row of this sequence counts nodes on the level n+1 with labels 0, 1, 2, 3, while the n-th row of A099423 counts nodes up to level n. - Andrey Zabolotskiy, Jan 06 2023
LINKS
Robert H. Barbour, 2D Four-Color Cellular Automaton, NKS 2006 Wolfram Science Conference.
Robert H. Barbour, Two-dimensional Four Color Cellular Automaton: Surface Explorations, Complex Systems, 17 (2007), 103-112.
FORMULA
Appears to satisfy a 12-degree linear recurrence. - Ralf Stephan, Dec 04 2004
MAPLE
Algorithm available from Robert H Barbour
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert H Barbour and L. D. Painter, Jun 01 2004
STATUS
approved