A364838 - OEIS

A364838

a(n) is the number of line intersections (including vertices) inside a regular n-gon after inscribing (always starting from the same point), for each proper divisor d_i of n greater than 1, a regular d_i-gon.

1, 2, 3, 4, 5, 7, 7, 8, 9, 11, 11, 21, 13, 15, 19, 16, 17, 26, 19, 31, 25, 23, 23, 53, 25, 27, 27, 39, 29, 73, 31, 32, 37, 35, 43, 86, 37, 39, 43, 79, 41, 91, 43, 55, 69, 47, 47, 121, 49, 62, 55, 63, 53, 87, 63, 99, 61, 59, 59, 253, 61, 63, 91, 64, 73, 123, 67

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OFFSET

1,2

COMMENTS

Inspired by an X (or Twitter) post by Matt Henderson (see links section).

LINKS

Table of n, a(n) for n=1..67.

Matt Henderson, X post, 2023.

Paolo Xausa, Illustration of first terms.

Paolo Xausa, Illustration of a(60).

FORMULA

a(n) = n if n is prime, a power of 2 or A032741(n) <= 2.