A336785 Consider the rectangular regions in the Even Conant Lattice; let S(0) be the singleton with the square at the origin, and for any n >= 0, let S(n+1) be the set of rectangular regions adjacent to some region in S(n) that are not found in S(0) U ... U S(n); a(n) is the number of regions in S(n).

1, 2, 3, 4, 8, 7, 10, 15, 13, 18, 18, 29, 22, 31, 29, 35, 36, 42, 53, 52, 55, 68, 82, 66, 87, 80, 87, 116, 124, 104, 124, 100, 132, 142, 160, 166, 161, 190, 173, 182, 237, 244, 289, 312, 331, 265, 259, 269, 265, 330, 386, 495, 565, 542, 449, 381, 436, 465, 486

Offset: 0

Author

Rémy Sigrist, Sep 20 2020

Keywords

• nonn

Comments

See A328078 for more information.

Two regions are considered adjacent if they share a common edge portion of size >= 1.

This is the coordination series (with respect to the point at the origin) for the dual graph to the graph of the Even Conant Lattice. - N. J. A. Sloane, Sep 20 2020

Examples

			See Illustration in Links section.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..338
• Rémy Sigrist, Illustration of initial terms
• Rémy Sigrist, C++ program for A336785
• Index entries for coordination sequences

Crossrefs

Cf. A328078, A337642.