A368815 Number of edges in a regular 2n-gon when all vertices are connect by straight lines except for the n lines joining diametrically opposite vertices.

0, 4, 24, 104, 320, 648, 1540, 2832, 3996, 7860, 12100, 15552, 25376, 35084, 36840, 62752, 81600, 97272, 131556, 163720, 178332, 245564, 296516, 336960, 421600, 497172, 557280, 678552, 786016, 836520, 1038500, 1185344, 1301124, 1525444, 1720740, 1893600, 2166720, 2419612, 2628600, 2991440

Offset

1,2

Comments

See A368813 and A368814 for images of the 2n-gons.

Links

Table of n, a(n) for n=1..40.

Formula

a(n) = A368813(n) + A368814(n) - 1 by Euler's formula.

Crossrefs

Cf. A368813 (regions), A368814 (vertices), A368816 (k-gons), A368757, A135565.

Sequence in context: A048806 A043009 A355798 * A006736 A165752 A366603

Adjacent sequences: A368812 A368813 A368814 * A368816 A368817 A368818

Keyword

nonn

Author

Scott R. Shannon, Jan 06 2024

Status

approved