A255540 Number of connected digital images in Z^2 (regarding each point as connected to its 8 neighbors) on n points up to isomorphism.

1, 1, 2, 6, 15, 51, 173, 681, 2682

Offset: 1

Author

P. Christopher Staecker, Feb 24 2015

Keywords

• nonn
• hard
• more

Comments

Also the number of polyplets (A030222) on n points up to isomorphism of adjacency graphs.

Examples

			For n=4 the a(4)=6 images are:
X   X X    X    XX    X     X
X    X    X X   XX   XX   XX
X    X     X         X     X
X
		

Links

• P. C. Staecker, Some enumerations of binary digital images, arXiv 1502.06236 [math.CO], 2015 (see table p. 6).
• P. C. Staecker, Digital image enumerations

Crossrefs

Cf. A255539.