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 A213992 #6 Jul 22 2025 23:06:21 %S A213992 172,1003,2546,8168,14030,28328,40370,64679,102377,151301,191708, %T A213992 290679,356931,445149,569583,787170,917169,1190970,1375176,1744554, %U A213992 2061684,2413461,2647641,3323763,3962721,4502277,5124586,6087406,6704266,7973326 %N A213992 Number of 3X3 0..n matrices whose square is also a 0..n matrix. %C A213992 Row 3 of A213990 %H A213992 R. H. Hardin, <a href="/A213992/b213992.txt">Table of n, a(n) for n = 1..210</a> %e A213992 Some solutions for n=3 %e A213992 ..0..0..2....1..2..1....0..3..0....0..2..1....0..1..3....1..1..0....0..1..0 %e A213992 ..0..1..1....0..0..0....0..1..1....0..0..0....0..0..1....0..0..3....0..1..0 %e A213992 ..0..1..1....1..0..0....0..2..0....0..0..1....0..0..0....0..0..0....0..1..1 %K A213992 nonn %O A213992 1,1 %A A213992 _R. H. Hardin_ Jun 30 2012