Sudoku Infinity?

[Walterloo]

Does anyone know how many completely different standard 9x9 sudoku puzzles are possible? With all the magazines and books available surely there must be some repeated grids out there?

[gen2]

6,670,903,752,021,072,936,960 different sudokus

Some of those will be reflections or rotations of others so if you want to discount those, there are just 5,472,730,538 possibilities.

But do you remember all the previous ones you have solved and when you see one again will you recognise it as one you solved 3 weeks ago?

[Walterloo]

Thanks for that! You're right about the fact that you probably won't recognise a repeat anyway. Unlike a crossword!