OFFSET
1,3
COMMENTS
Start with a single regular heptagon. The heptagon fractal is constructed by taking with the previous completed step, and overlapping it in its entirety to each vertex (excluding the top vertex as they overlap completely). Once constructed, any unobscured heptagons within are counted. "Unobscured" means no lines cross through it, and its shape is regular. See links for images.
LINKS
Gavin Lupo, Heptagon Construction, the initial steps
Gavin Lupo, Step 5
EXAMPLE
Start with a(1) = 1 unobscured heptagon. For the next step, take step 1's entire shape and place it at each vertex. Although the total number of heptagons is 7, only 1 unobscured heptagon remains, so a(2) = 1.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gavin Lupo, Mar 29 2024
STATUS
approved