Each box of a sudoku grid may have x clues with 0 ≤ x ≤ 9; it makes 10 possibilities.
Therefore, there are 10^9 = 1,000,000,000 possible ways to fill in the 9 boxes.
Here is an example - 27 clues:
- Code: Select all
246
302
901
How many are non equivalent (ed) ?
The answer is 14,068,450.
Here is the breakdown by the total number of clues (n) in the grid:
- Code: Select all
n
0 1
1 1
2 3
3 7
4 16
5 32
6 68
7 126
8 238
9 422
10 729
11 1211
12 1973
13 3097
14 4764
15 7132
16 10451
17 14959
18 21007
19 28877
20 38998
21 51682
22 67332
23 86222
24 108680
25 134776
26 164649
27 198125
28 234987
29 274727
30 316784
31 360248
32 404243
33 447599
34 489165
35 527695
36 562042
37 591010
38 613688
39 629268
40 637191
41 637191
42 629268
43 613688
44 591010
45 562042
46 527695
47 489165
48 447599
49 404243
50 360248
51 316784
52 274727
53 234987
54 198125
55 164649
56 134776
57 108680
58 86222
59 67332
60 51682
61 38998
62 28877
63 21007
64 14959
65 10451
66 7132
67 4764
68 3097
69 1973
70 1211
71 729
72 422
73 238
74 126
75 68
76 32
77 16
78 7
79 3
80 1
81 1
----------
14068450
For instance, for n=4, here are the 16 possibilities:
- Code: Select all
000 000 000 000
000 000 000 000
004 013 022 112
000 000 000 000
001 001 001 001
012 021 030 111
000 000 000 000
001 002 002 011
120 020 110 011
000 001 001 001
011 001 010 010
101 110 101 200
Now, if boxes with only 0,1 or 9 clues are considered, the ed-number of ways to fill in the grid is 438 out of 3^9 = 19683
Here they are:
- Code: Select all
000000000
000000001
000000009
000000011
000000019
000000099
000000111
000000119
000000199
000000999
000001010
000001011
000001019
000001090
000001091
000001099
000001110
000001111
000001119
000001190
000001191
000001199
000001990
000001991
000001999
000009090
000009091
000009099
000009110
000009111
000009119
000009190
000009191
000009199
000009990
000009991
000009999
000011011
000011019
000011099
000011101
000011109
000011111
000011119
000011199
000011901
000011909
000011911
000011919
000011999
000019091
000019099
000019109
000019111
000019119
000019190
000019191
000019199
000019909
000019910
000019911
000019919
000019990
000019991
000019999
000099099
000099111
000099119
000099199
000099909
000099911
000099919
000099999
000111111
000111119
000111199
000111999
000119119
000119191
000119199
000119991
000119999
000199199
000199919
000199999
000999999
001001110
001001111
001001119
001001190
001001191
001001199
001001990
001001991
001001999
001009190
001009191
001009199
001009990
001009991
001009999
001010100
001010101
001010109
001010111
001010119
001010199
001010900
001010901
001010909
001010911
001010919
001010999
001011110
001011111
001011119
001011190
001011191
001011199
001011900
001011901
001011909
001011910
001011911
001011919
001011990
001011991
001011999
001019190
001019191
001019199
001019900
001019901
001019909
001019910
001019911
001019919
001019990
001019991
001019999
001090900
001090901
001090909
001090910
001090911
001090919
001090990
001090991
001090999
001091110
001091111
001091119
001091190
001091191
001091199
001091901
001091909
001091910
001091911
001091919
001091990
001091991
001091999
001099190
001099191
001099199
001099909
001099910
001099911
001099919
001099990
001099991
001099999
001110110
001110111
001110119
001110190
001110191
001110199
001110990
001110991
001110999
001111111
001111119
001111190
001111191
001111199
001111990
001111991
001111999
001119119
001119190
001119191
001119199
001119990
001119991
001119999
001190191
001190199
001190910
001190911
001190919
001190990
001190991
001190999
001191191
001191199
001191911
001191919
001191990
001191991
001191999
001199199
001199919
001199990
001199991
001199999
001990990
001990991
001990999
001991991
001991999
001999999
009009990
009009991
009009999
009011910
009011911
009011919
009011990
009011991
009011999
009019990
009019991
009019999
009090900
009090901
009090909
009090911
009090919
009090999
009091910
009091911
009091919
009091990
009091991
009091999
009099990
009099991
009099999
009110110
009110111
009110119
009110190
009110191
009110199
009110990
009110991
009110999
009111111
009111119
009111190
009111191
009111199
009111990
009111991
009111999
009119119
009119190
009119191
009119199
009119990
009119991
009119999
009190191
009190199
009190910
009190911
009190919
009190990
009190991
009190999
009191191
009191199
009191911
009191919
009191990
009191991
009191999
009199199
009199919
009199990
009199991
009199999
009990990
009990991
009990999
009991991
009991999
009999999
011101110
011101111
011101119
011101190
011101191
011101199
011101990
011101991
011101999
011109190
011109191
011109199
011109910
011109911
011109919
011109990
011109991
011109999
011111111
011111119
011111199
011111901
011111909
011111911
011111919
011111999
011119191
011119199
011119901
011119909
011119910
011119911
011119919
011119990
011119991
011119999
011199199
011199901
011199909
011199911
011199919
011199999
011901990
011901991
011901999
011909911
011909919
011909990
011909991
011909999
011911911
011911919
011911999
011919919
011919991
011919999
011999999
019109990
019109991
019109999
019111910
019111911
019111919
019111990
019111991
019111999
019119990
019119991
019119999
019190901
019190909
019190911
019190919
019190991
019190999
019191910
019191911
019191919
019191990
019191991
019191999
019199990
019199991
019199999
019909990
019909991
019909999
019910919
019910999
019911911
019911919
019911990
019911991
019911999
019919919
019919990
019919991
019919999
019990991
019990999
019991991
019991999
019999999
099909990
099909991
099909999
099911911
099911919
099911999
099919991
099919999
099999999
111111111
111111119
111111199
111111999
111119191
111119199
111119991
111119999
111199199
111199919
111199999
111999999
119119991
119119999
119191911
119191919
119191999
119199991
119199999
119991991
119991999
119999999
199919991
199919999
199999999
999999999
Obviously, some patterns can't have valid puzzles: 000019119 for example.
- Code: Select all
000
019
119
More to come.
JPF