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A331765 Number of edges formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) rectangular grid of points (or equally, a 2 X n grid of squares).

%I A331765 #29 Aug 27 2020 06:03:04
%S A331765 28,92,240,508,944,1548,2520,3754,5392,7528,10296,13570,17844,22768,
%T A331765 28584,35704,44048,53380,64728,77292,91500,107828,126408,146772,
%U A331765 170080,195580,223764,255010,289792,326996,369320,414908,463880,517724,575404,637530,706172
%N A331765 Number of edges formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) rectangular grid of points (or equally, a 2 X n grid of squares).
%C A331765 Triangles A331452, A331453, A331454 do not have formulas, except for column 1. The column 2 sequences, A331763, A331765, A331766, are therefore the next ones to attack.
%C A331765 See A331452 for other illustrations.
%H A331765 Lars Blomberg, <a href="/A331765/b331765.txt">Table of n, a(n) for n = 1..100</a>
%H A331765 Scott R. Shannon, <a href="/A331452/a331452_13.png">Colored illustration for a(3) = 240.</a>
%H A331765 Scott R. Shannon, <a href="/A331452/a331452_1.txt">Data specifically for nX2 (or 2Xn) rectangles</a>
%H A331765 N. J. A. Sloane (in collaboration with Scott R. Shannon), <a href="/A331452/a331452.pdf">Art and Sequences</a>, Slides of guest lecture in Math 640, Rutgers Univ., Feb 8, 2020. Mentions this sequence.
%Y A331765 Column 2 of A331454.
%Y A331765 Cf. A331763, A331766.
%K A331765 nonn
%O A331765 1,1
%A A331765 _Scott R. Shannon_ and _N. J. A. Sloane_, Feb 05 2020
%E A331765 More terms from _Scott R. Shannon_, Mar 11 2020
%E A331765 a(21) and beyond from _Lars Blomberg_, Apr 28 2020