%I #15 Aug 12 2023 00:42:18

%S 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,

%T 27,39,29,73,31,32,37,35,43,86,37,39,43,79,41,91,43,55,69,47,47,121,

%U 49,62,55,63,53,87,63,99,61,59,59,253,61,63,91,64,73,123,67

%N 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.

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

%H Matt Henderson, <a href="https://twitter.com/matthen2/status/1639925895254224898">X post</a>, 2023.

%H Paolo Xausa, <a href="/A364838/a364838.pdf">Illustration of first terms</a>.

%H Paolo Xausa, <a href="/A364838/a364838_1.pdf">Illustration of a(60)</a>.

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

%F a(n) = A364830(n) + n.

%Y Cf. A006561, A007569, A032741, A364828, A364829, A364830.

%K nonn

%O 1,2

%A _Paolo Xausa_, Aug 09 2023