cp's OEIS Frontend

A291188 Number of inequivalent 2 X n Sudoku grids ((2*n) X (2*n) grids divided into 2 X n boxes).

%I A291188 #28 Feb 16 2022 23:23:02
%S A291188 2,49,1673187,4743933602050718
%N A291188 Number of inequivalent 2 X n Sudoku grids ((2*n) X (2*n) grids divided into 2 X n boxes).
%C A291188 We regard two grids as inequivalent if one cannot be transformed into another by some sequence of symmetries, or by relabeling. For the 2 X 3 Sudoku grids case the allowed equivalences are (see link to Jarvis):
%C A291188 - relabeling entries; reflection; rotation;
%C A291188 - permutation of blocks of columns 1-2, 3-4 and 5-6;
%C A291188 - permutation of blocks of rows 1-3 and 4-6;
%C A291188 - permutation of columns 1-2;
%C A291188 - permutation of columns 3-4;
%C A291188 - permutation of columns 5-6;
%C A291188 - permutation of rows 1-3;
%C A291188 - permutation of rows 4-6.
%H A291188 Frazer Jarvis, <a href="http://www.afjarvis.staff.shef.ac.uk/sudoku/">Sudoku enumeration problems</a>
%H A291188 Jordy Vanpoucke, <a href="http://homepages.vub.ac.be/~jvpoucke/MasterThesisMOLS.pdf">Mutually orthogonal latin squares and their generalizations</a>
%e A291188 a(2) = 2:
%e A291188 .
%e A291188   12|34  12|34
%e A291188   34|12  34|12
%e A291188   --+--  --+--
%e A291188   21|43  23|41
%e A291188   43|21  41|23
%e A291188 .
%e A291188 An example of 2 X 3 Sudoku grids:
%e A291188 .
%e A291188   14|25|36
%e A291188   35|16|24
%e A291188   26|34|15
%e A291188   --+--+--
%e A291188   41|52|63
%e A291188   52|63|41
%e A291188   63|41|52
%Y A291188 Cf. A109741, A291187.
%K A291188 nonn,more
%O A291188 2,1
%A A291188 _Seiichi Manyama_, Aug 19 2017