The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A169649 Total number of cells that are ON at stage n in Wolfram's 2-D cellular automaton defined by Rule 942. 4
0, 1, 5, 9, 21, 29, 41, 53, 89, 117, 129, 141, 177, 205, 241, 277, 385, 485, 497, 509, 545, 573, 609, 645, 753, 845, 881, 917, 1025, 1109, 1217, 1325, 1649, 1989, 2001, 2013, 2049, 2077, 2113, 2149, 2257, 2349, 2385, 2421, 2529, 2613, 2721, 2829 (list; graph; refs; listen; history; text; internal format)
OFFSET
-1,3
COMMENTS
We work on the square grid. A cell is turned ON iff exactly one or four of its four neighbors is ON. Once a cell is ON it stays ON. At stage -1 all cells are OFF. At stage 0 a single cell is turned ON.
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 928.
LINKS
David Applegate, The movie version
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]
MATHEMATICA
Map[Function[Apply[Plus, Flatten[ #1]]], CellularAutomaton[{ 942, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 100]]
ArrayPlot /@ CellularAutomaton[{942, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 23]
CROSSREFS
Partial sums of A169648.
Sequence in context: A186297 A272986 A273642 * A273739 A169709 A269523
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 07 2010
EXTENSIONS
Added Mma programs and illustrations. - N. J. A. Sloane, Sep 21 2014
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 13 09:43 EDT 2024. Contains 373383 sequences. (Running on oeis4.)