# Sudoku question

Pawnokeyhole
Posers and Puzzles 22 Jun '05 09:45
1. Pawnokeyhole
Krackpot Kibitzer
22 Jun '05 09:45
I tried and solved my first (easy) Sudoku puzzle recently. It set me to wondering however: What is fewest number of initial entries into a 9 x 9 sudoku grid that permit such a puzzle to be solved? I suspect the number can be formally arrived at, but I don't know how. Any takers?

Aiden
2. sonhouse
Fast and Curious
22 Jun '05 10:41
On the sudoku site the puzzles there show either 3 or 4 numbers
in each sub grid. So your only possiblity is 1 or 2 as smaller, not
much of a range. 1 you could eliminate as allowing many solutions
so the idea is to figure out if 2 in each grid could be set up
to have only one solution, I think not. I think with 2 in each grid you
have many more solutions so it looks to me like 3 and 4 are the
minimum already.
3. Palynka
Upward Spiral
22 Jun '05 12:25
17 is the answer.
4. sonhouse
Fast and Curious
22 Jun '05 15:18
Originally posted by Palynka
17 is the answer.
I had considered that, as well as 69 but the philosophical implications
stymied me from venturing a valid logically unimpeachable arguement
considered as a devils advocacy type of involvement with the
fundamental numerical formulations.
5. The Plumber
Leak-Proof
22 Jun '05 17:03
Originally posted by Palynka
17 is the answer.
Huh uh...42. You should know that!
6. XanthosNZ
Cancerous Bus Crash
22 Jun '05 19:071 edit
+ 3 + + + + 9 + +
6 + + 4 + + + + +
+ + + + + + 7 + +
+ 7 + 2 9 + + + +
+ + + 3 + + + 6 +
+ + + + + + + 4 +
4 + + + + 5 + 8 +
+ + + + 7 + 3 + +
+ + 1 + + + + + +

OK I doubt this will work. But there is a 17 number setup with a unique solution. No 16 numbers setups with unique solutions have been discovered but they haven't been shown not to exist.

EDIT: Well it worked kind of.
7. The Plumber
Leak-Proof
22 Jun '05 19:59
Oh, you meant 17 was the answer to the Soduku thing, I was thinking of Life, the Universe, and Everything.

nevermind....ðŸ˜€
8. Palynka
Upward Spiral
22 Jun '05 20:09
Originally posted by The Plumber
Oh, you meant 17 was the answer to the Soduku thing, I was thinking of Life, the Universe, and Everything.

nevermind....ðŸ˜€
The answer to that is, of course, the answer to the Soduku thing added to the number of months of the year and a lot of bad luck.

That's how I got to the answer to the Soduku thing

42 = 12 + 13 + X
X = 17
9. sonhouse
Fast and Curious
22 Jun '05 22:14
Originally posted by XanthosNZ
+ 3 + + + + 9 + +
6 + + 4 + + + + +
+ + + + + + 7 + +
+ 7 + 2 9 + + + +
+ + + 3 + + + 6 +
+ + + + + + + 4 +
4 + + + + 5 + 8 +
+ + + + 7 + 3 + +
+ + 1 + + + + ...[text shortened]... have been discovered but they haven't been shown not to exist.

EDIT: Well it worked kind of.
well that blows my 3 and 4 thing. The puzzle I saw on the sudoku
site had 6 3's and 3 4's (30) It just seemed to allow more
solutions if you had less occupied squares.
So the key is the *position* in the squares.
10. sonhouse
Fast and Curious
22 Jun '05 22:34
check out this site:
http://www.shef.ac.uk/~pm1afj/sudoku/
11. sonhouse
Fast and Curious
22 Jun '05 22:36
also this one:
http://en.wikipedia.org/wiki/Sudoku#Rules_and_terminology
12. orfeo
Paralysed analyst
28 Jun '05 22:16
Originally posted by sonhouse
well that blows my 3 and 4 thing. The puzzle I saw on the sudoku
site had 6 3's and 3 4's (30) It just seemed to allow more
solutions if you had less occupied squares.
So the key is the *position* in the squares.
They've just started doing these in my local newspaper. The ones I've seen have 3 or 4 entries in SOME subsquares, but definitely not every subsquare.