A194601 Number of ON cells after n generations of the 2D cellular automaton described in the comments.

1, 8, 16, 36, 40, 68, 72, 116, 128, 180, 204, 256, 292, 332, 368, 500, 480, 492, 700, 592, 820, 760, 976, 992, 1096, 1132, 1332, 1344, 1488, 1580, 1680, 1812, 1848, 1996, 2156, 2168, 2140, 2624, 2572, 2680, 3008, 2980, 3396, 2960, 3804, 3356, 4420, 3868, 4236, 4284

Offset

1,2

Comments

The cells are the squares of the standard square grid. All cells are initially OFF and one cell is turned ON at generation 1. At subsequent generations a cell is ON if and only if (1) exactly one of the four nearest side neighbors was ON or (2) exactly one of the four nearest corner neighbors was ON in the previous generation.(If exactly one side (corner) was ON, it does not matter how many corners (sides) were ON.)

Links

Table of n, a(n) for n=1..50.

John W. Layman, Graphs of the automaton for generations 1-15

Mathematica

(* Mathematica 8.0*) ca = CellularAutomaton[{2165730, {2, {{5, 1, 5}, {1, 0, 1}, {5, 1, 5}}}, {1, 1}}, {{{1}}, 0}, 50, 51];  a = Table[Total[ca[[i]], 2], {i, 1, 50}]

Crossrefs

Sequence in context: A058516 A366511 A217672 * A200271 A197986 A054301

Adjacent sequences: A194598 A194599 A194600 * A194602 A194603 A194604

Keyword

nonn

Author

John W. Layman, Aug 30 2011

Status

approved