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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.

%I A367277 #12 Nov 12 2023 02:11:31
%S A367277 0,1,57,329,1317,2861,7417,12801,23329,36549,64625,80085,138261,
%T A367277 176829,233705,311949,455205,513205,741889,819509,1046161,1310673,
%U A367277 1692869,1772001,2315189,2713893,3165017,3552641,4538729,4602865,6015437,6432553,7421213,8550349,9439481,10063849,12635621
%N 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.
%C A367277 See A367276 for further information.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277.png">Image for n = 1</a>.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277_1.png">Image for n = 2</a>.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277_2.png">Image for n = 3</a>.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277_3.png">Image for n = 4</a>.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277_4.png">Image for n = 5</a>.
%H A367277 Scott R. Shannon, <a href="/A367277/a367277_5.png">Image for n = 10</a>.
%F A367277 a(n) = A367279(n) - A367278(n) - 4*n - 3 (Euler).
%Y A367277 Cf. A367276 (interior), A367278 (regions), A367279 (edges).
%K A367277 nonn
%O A367277 0,3
%A A367277 _Scott R. Shannon_, Nov 11 2023