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 A209733 #7 Jul 22 2025 21:55:55 %S A209733 21976,775096,28927984,1138541280,45147495264,1809791149768, %T A209733 72515584004736,2914488537817408,117033599127615880, %U A209733 4704742675739474176,189030631236371886792,7598451666243980931808,305353336500744007552616 %N A209733 1/4 the number of (n+1)X6 0..3 arrays with every 2X2 subblock having distinct edge sums. %C A209733 Column 5 of A209736 %H A209733 R. H. Hardin, <a href="/A209733/b209733.txt">Table of n, a(n) for n = 1..210</a> %e A209733 Some solutions for n=4 %e A209733 ..1..1..1..3..3..3....1..0..0..0..0..3....0..3..2..3..1..1....0..2..1..0..1..2 %e A209733 ..2..3..0..0..1..2....1..3..1..2..1..3....2..3..0..0..0..3....1..3..3..2..3..3 %e A209733 ..1..3..2..3..1..3....1..0..0..2..0..3....0..1..1..2..1..3....0..0..1..0..0..1 %e A209733 ..1..0..2..0..0..3....1..3..1..2..1..1....2..2..3..3..1..0....3..2..2..2..3..1 %e A209733 ..1..3..2..1..2..3....1..2..0..0..0..3....3..0..0..2..1..3....0..0..3..0..3..2 %K A209733 nonn %O A209733 1,1 %A A209733 _R. H. Hardin_ Mar 12 2012