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 A207729 #7 Jul 22 2025 20:44:20 %S A207729 2,4,4,6,16,6,9,36,36,9,15,81,78,81,14,25,225,169,189,196,21,40,625, %T A207729 611,441,490,441,31,64,1600,2209,2163,1225,1113,961,46,104,4096,6016, %U A207729 10609,8575,2809,2449,2116,68,169,10816,16384,33063,60025,27931,6241,5474,4624 %N A207729 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically. %C A207729 Table starts %C A207729 ..2....4....6.....9.....15......25.......40.......64........104.........169 %C A207729 ..4...16...36....81....225.....625.....1600.....4096......10816.......28561 %C A207729 ..6...36...78...169....611....2209.....6016....16384......51840......164025 %C A207729 ..9...81..189...441...2163...10609....33063...103041.....418263.....1697809 %C A207729 .14..196..490..1225...8575...60025...211680...746496....4078944....22287841 %C A207729 .21..441.1113..2809..27931..277729..1029231..3814209...27996255...205492225 %C A207729 .31..961.2449..6241..88243.1247689..4799749.18464209..184732327..1848226081 %C A207729 .46.2116.5474.14161.288813.5890329.23473944.93547584.1307760792.18282014521 %H A207729 R. H. Hardin, <a href="/A207729/b207729.txt">Table of n, a(n) for n = 1..649</a> %e A207729 Some solutions for n=4 k=3 %e A207729 ..0..0..1....1..1..0....1..1..0....1..1..1....1..1..1....1..1..1....1..0..0 %e A207729 ..1..1..1....1..1..1....1..0..1....0..0..1....0..1..1....1..1..1....1..1..0 %e A207729 ..0..0..1....1..0..0....1..0..0....0..0..1....0..1..1....1..1..0....1..0..0 %e A207729 ..0..0..1....1..0..0....1..0..0....1..1..0....1..1..1....1..0..0....1..0..0 %Y A207729 Column 1 is A038718(n+2) %Y A207729 Column 2 is A207069 %Y A207729 Row 1 is A006498(n+2) %Y A207729 Row 2 is A189145(n+2) %K A207729 nonn,tabl %O A207729 1,1 %A A207729 _R. H. Hardin_ Feb 19 2012