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 A190317 #26 May 28 2021 19:54:06 %S A190317 0,0,8,48,164,448,976,1864,3328,5512,8640,12984,18836,26576,36584, %T A190317 49056,64560,83640,106904,134816,168004,206952,252480,305360,366312, %U A190317 436120,515864,605928,707644,822120,950216,1092784,1251784,1427848,1622416,1835968,2070404 %N A190317 Number of acute isosceles triangles on an n X n grid. %C A190317 Place all bounding boxes of A279418 that will fit into the n X n grid in all possible positions, and the proper rectangles in two orientations: a(n) = Sum(i=1..n, Sum(j=1..i, k * (n-i+1) * (n-j+1) * A279418(i,j))) where k=1 when i=j and k=2 otherwise. - _Lars Blomberg_, Mar 02 2017 %H A190317 Lars Blomberg, <a href="/A190317/b190317.txt">Table of n, a(n) for n = 1..10000</a> (the first 100 terms from Chai Wah Wu) %F A190317 a(n) = A186434(n) - A187452(n) - A190318(n). %Y A190317 Cf. A186434, A187452, A190318, A279418. %K A190317 nonn %O A190317 1,3 %A A190317 _Martin Renner_, May 08 2011 %E A190317 a(10)-a(37) from _Nathaniel Johnston_, May 09 2011