Counts only distinct strict still lifes; reflections and rotations are removed. Pseudo-still lifes (e.g., patterns made up of two disjoint still lifes) are not counted.
Table of n, a(n) for n=1..13.
a(4)=2 because there are only two still-lives with four cells: the block (a 2x2 block) and the tub (four cells bordering all four sides of an empty spot).
Cf. A019473, A166476
Sequence in context: A195691 A074763 A099932 * A008346 A119282 A241513
Adjacent sequences: A174997 A174998 A174999 * A175001 A175002 A175003
Christian Schroeder, Apr 03 2010