A371620 Fractal sequence based on a heptagon: a(n) = number of unobscured heptagons remaining after completing step n.0

1, 1, 8, 48, 266

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

Table of n, a(n) for n=1..5.

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

Cf. A371536.

Sequence in context: A026706 A128734 A006321 * A295047 A295375 A081554

Adjacent sequences: A371616 A371617 A371619 * A371621 A371622 A371623

Keyword

nonn,more

Author

Gavin Lupo, Mar 29 2024

Status

approved