A367277 Place n equally spaced points on each side of a square, and join each of these points by a chord to the 3*n new points on the other three sides: sequence gives number of interior vertices in the resulting planar graph.

0, 1, 57, 329, 1317, 2861, 7417, 12801, 23329, 36549, 64625, 80085, 138261, 176829, 233705, 311949, 455205, 513205, 741889, 819509, 1046161, 1310673, 1692869, 1772001, 2315189, 2713893, 3165017, 3552641, 4538729, 4602865, 6015437, 6432553, 7421213, 8550349, 9439481, 10063849, 12635621

Offset: 0

Author

Scott R. Shannon, Nov 11 2023

Keywords

• nonn

Comments

See A367276 for further information.

Links

• Scott R. Shannon, Image for n = 1.
• Scott R. Shannon, Image for n = 2.
• Scott R. Shannon, Image for n = 3.
• Scott R. Shannon, Image for n = 4.
• Scott R. Shannon, Image for n = 5.
• Scott R. Shannon, Image for n = 10.

Crossrefs

Cf. A367276 (interior), A367278 (regions), A367279 (edges).

Formula

a(n) = A367279(n) - A367278(n) - 4*n - 3 (Euler).