login
Number of fair sudoku problems with n given values on a 4 x 4 grid.
0

%I #5 Mar 30 2012 17:28:13

%S 0,0,0,0,25728,284160,1041408,2141184,2961024,2958336,2204928,1239552,

%T 522624,161280,34560,4608,288

%N Number of fair sudoku problems with n given values on a 4 x 4 grid.

%C A problem is 'fair' if the given values 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).

%e 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.

%Y Cf. A107739.

%K fini,full,nonn

%O 0,5

%A _Hugo van der Sanden_, Aug 19 2005