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Search: id:A109252
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| A109252 |
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Number of fair sudoku problems with n given digits on a 4 x 4 grid. |
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+0
1
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| 0, 0, 0, 0, 25728, 284160, 1041408, 2141184, 2961024, 2958336, 2204928, 1239552, 522624, 161280, 34560, 4608, 288
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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A problem is 'fair' if the given digits are sufficient to resolve the entire grid to a unique Sudoku solution. Since a(16) represents problems in which the whole grid is already given, a(16) is necessarily the same as A107739(2).
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EXAMPLE
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An example fair problem with 4 given digits is ?4?2 / ???1 / ???? / ?3??, which has the complete grid 1432 / 3241 / 4123 / 2314 as the only solution. There are 25,728 such fair problems with 4 given digits, so a(4) = 25728.
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CROSSREFS
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Cf. A107739.
Sequence in context: A031837 A023350 A115535 this_sequence A003927 A115494 A034622
Adjacent sequences: A109249 A109250 A109251 this_sequence A109253 A109254 A109255
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KEYWORD
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fini,full,nonn
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AUTHOR
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Hugo van der Sanden (hv(AT)crypt.org), Aug 19 2005
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