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 A286919 #26 Apr 29 2019 06:16:03 %S A286919 1,1,8,1,36,1072,1,288,66816,33693696,1,2080,4197376,17184194560, %T A286919 70368756760576,1,16640,268517376,8796399206400,288230393868451840, %U A286919 9444732983468915425280,1,131328,17180065792,4503616874348544,1180591620768950910976,309485009825866260538195968,81129638414606695206587887255552 %N A286919 Triangle read by rows: T(n,m) is the number of pattern classes in the (n,m)-rectangular grid with 8 colors and n>=m, two patterns are in the same class if one of them can be obtained by a reflection or 180-degree rotation of the other. %C A286919 Computed using Burnsides orbit-counting lemma. %H A286919 María Merino, <a href="/A286919/b286919.txt">Rows n=0..35 of triangle, flattened</a> %H A286919 M. Merino and I. Unanue, <a href="https://doi.org/10.1387/ekaia.17851">Counting squared grid patterns with Pólya Theory</a>, EKAIA, 34 (2018), 289-316 (in Basque). %F A286919 For even n and m: T(n,m) = (8^(m*n) + 3*8^(m*n/2))/4; %F A286919 for even n and odd m: T(n,m) = (8^(m*n) + 8^((m*n+n)/2) + 2*8^(m*n/2))/4; %F A286919 for odd n and even m: T(n,m) = (8^(m*n) + 8^((m*n+m)/2) + 2*8^(m*n/2))/4; %F A286919 for odd n and m: T(n,m) = (8^(m*n) + 8^((m*n+n)/2) + 8^((m*n+m)/2) + 8^((m*n+1)/2))/4. %e A286919 Triangle begins: %e A286919 ======================================================== %e A286919 n\m | 0 1 2 3 4 %e A286919 ----|--------------------------------------------------- %e A286919 0 | 1 %e A286919 1 | 1 8 %e A286919 2 | 1 36 1072 %e A286919 3 | 1 288 66816 33693696 %e A286919 4 | 1 2080 4197376 17184194560 70368756760576 %e A286919 ... %Y A286919 Cf. A225910, A283432, A283433, A283434, A286893, A286895. %K A286919 nonn,tabl %O A286919 0,3 %A A286919 _María Merino_, Imanol Unanue, _Yosu Yurramendi_, May 16 2017