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 A189813 #7 Jul 22 2025 11:55:16 %S A189813 158,550,1236,2250,3596,5250,7224,9496,12044,14860,17948,21266,24852, %T A189813 28634,32604,36780,41168,45716,50440,55324,60384,65612,71000,76532, %U A189813 82240,88116,94136,100300,106624,113100,119744,126532,133472,140560,147792 %N A189813 Number of right triangles on a (n+1)X9 grid. %C A189813 Column 8 of A189814 %H A189813 R. H. Hardin, <a href="/A189813/b189813.txt">Table of n, a(n) for n = 1..200</a> %F A189813 Empirical: a(n) = 72*n^2 + 2344*n - 23112 for n>63 %e A189813 Some solutions for n=3 %e A189813 ..2..8....2..2....0..6....0..6....3..0....1..3....0..2....0..8....3..5....3..8 %e A189813 ..2..1....2..7....0..5....0..4....0..0....0..3....0..1....0..7....1..1....0..8 %e A189813 ..3..8....3..2....2..6....1..6....3..8....1..7....1..2....3..8....1..6....3..7 %K A189813 nonn %O A189813 1,1 %A A189813 _R. H. Hardin_ Apr 28 2011