This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A331767 #20 Apr 28 2020 06:37:18 %S A331767 7,29,89,201,387,641,1067,1599,2305,3233,4431,5855,7721,9853,12369, %T A331767 15477,19093,23141,28073,33557,39699,46773,54815,63681,73825,84833, %U A331767 97005,110579,125587,141733,160063,179913,201105,224409,249329,276215,305925,337345,370793 %N A331767 Number of interior vertices formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) square grid. %C A331767 Same as A331763, but only count interior crossings. %C A331767 See A331452 for other illustrations. %H A331767 Lars Blomberg, <a href="/A331767/b331767.txt">Table of n, a(n) for n = 1..100</a> %H A331767 Scott R. Shannon, <a href="/A331452/a331452_13.png">Colored illustration for a(3) = 89.</a> %Y A331767 Cf. A331763, A331765, A331766. %K A331767 nonn %O A331767 1,1 %A A331767 _Scott R. Shannon_ and _N. J. A. Sloane_, Feb 05 2020 %E A331767 Needs to be extended using the new data for A331763. - _N. J. A. Sloane_, Mar 12 2020 %E A331767 a(10) and beyond from _Lars Blomberg_, Apr 28 2020