A056613 Number of n-celled pseudo still lifes in Conway's Game of Life, up to rotation and reflection.

0, 0, 0, 0, 0, 0, 0, 1, 1, 7, 16, 55, 110, 279, 620, 1645, 4067, 10843, 27250, 70637, 179011, 462086, 1184882, 3069135, 7906676, 20463274, 52816265, 136655095, 353198379, 914075620, 2364815358, 6123084116, 15851861075, 41058173683

Offset: 1

Author

N. J. A. Sloane, Aug 28 2000

Keywords

• nonn
• hard
• more

Comments

There are two slightly different possible definitions for a pseudo still life: a still life that can be partitioned into exactly two different still lifes, or a still life that can be partitioned into two *or more* still lifes. This sequence uses the latter definition. The first point in the sequence where this makes a difference is a(32) = 6123084116, which would be a(32) = 6123084115 under the former definition. - Nathaniel Johnston, May 25 2017

Examples

			For n = 8, the unique pseudo still life is a pair of 2 X 2 blocks occupying a 5 X 2 bounding box.
		

Links

• S. Ekström, Enumerating Still Lifes (in C)
• Mark D. Niemiec, Life Object Counts

Crossrefs

Cf. A019473, A330283.

Extensions

a(24) corrected by Nathaniel Johnston, Aug 26 2016 at the suggestion of Mark Niemiec

a(25)-a(30) computed by Simon Ekström and inserted by Adam P. Goucher, Jan 08 2017

a(24) corrected by Nathaniel Johnston, Feb 21 2017 (computed by Simon Ekström)

a(31)-a(32) from Nathaniel Johnston, using a script made by Simon Ekström, May 25 2017

a(33) from Nathaniel Johnston, using a script made by Simon Ekström, Apr 05 2019

a(34) from Nathaniel Johnston, using a script made by Simon Ekström, Jan 09 2020