A151731 Number of ON states after n generations of cellular automaton based on square grid with each cell adjacent to its eight neighbors.

0, 2, 6, 14, 20, 32, 40, 54, 70, 94, 108, 128, 152, 172, 188, 224, 256, 300, 344, 380, 416, 464, 504, 552, 598, 658, 728, 772, 816, 880, 940, 1000, 1076, 1148, 1212, 1276, 1360, 1454, 1556, 1624, 1708, 1796, 1912, 2004, 2124, 2250, 2376, 2480

Offset: 0

Author

N. J. A. Sloane, Jun 15 2009

Keywords

• nonn

Comments

A cell is turned ON if exactly two of its eight neighbors is ON. An ON cell remains ON forever.

We start with two edge-adjacent ON cells.

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..8192
• Rémy Sigrist, PARI program for A151731
• Rémy Sigrist, Illustration of the structure at stage 512

Crossrefs

See A151725, A151726 for the same CA except that exactly one neighbor must be ON for a cell to turn ON.

Cf. A151732, A151733, A151734.

Programs

PARI

\\ See Links section.