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A325954
Langton's ant on a three-dimensional grid: number of blue cells on the grid after n moves of the ant.
9
0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 2, 2, 3, 4, 4, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 4, 4, 4, 5, 5, 5, 5, 4, 5, 6, 6, 7, 8, 8, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 8, 9, 10, 9, 9, 10, 10, 10, 10, 9, 8, 8, 8, 7, 8, 8, 8, 8, 7, 8, 9
OFFSET
0,19
COMMENTS
The ant starts on a completely white grid.
Order of operations: turn 90 degrees, change cell color, move forward one unit.
The rules governing the movement of the ant and the change of cell colors are shown in the following table:
Cell color at | Direction of | Color the cell is
start of iteration | 90-degree turn | changed to
--------------------------------------------------------
white | right | black
black | left | blue
blue | up | yellow
yellow | down | white
LINKS
Wikipedia, Langton's ant.
Index entries for linear recurrences with constant coefficients, signature (2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-1).
FORMULA
a(n) = a(n-28) + 2 for n >= 93504. - Jinyuan Wang, Jul 13 2025
Recurrence: a(n) = 2*a(n-1) - 2*a(n-2) + 2*a(n-3) - 2*a(n-4) + ... + 2*a(n-27) - a(n-28) for n >= 93504. - Jianing Song, Jul 31 2026
EXAMPLE
See illustration in links.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Felix Fröhlich, May 28 2019
EXTENSIONS
a(51)-a(80) from Charlie Neder, Jun 06 2019
STATUS
approved