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# Game of Go

Go is an abstract board game for two players, in which the aim is to surround more territory than the opponent.[1]

The number of legal positions in Go played on an
 19 × 19
grid (where each group must have at least one liberty) is (A094777
 (19)
) the
 371 (9 × 19)
digits number
 212667732900366224249789357650440598098805861083269127196623872213228196352455447575029701325

with binary representation (566 binary digits)

``` 11011100101000101101111100110100010100111010100100111000111110111000111000000000111011100001010000010010100111101110000101001000101110111001100111001100001011001100111100011011001101000011000101010000001100111111111000000011011010001010110010100010010111010110001011010101101111000110011011000101000101000101010010101011110001011010101011001100111000101100111001010111111101100110111100110001111011100100110110010000011110100010010010000011000101101000111111011010111011111111101011001111000010010010110111000001001000010010000010100100110001100011100001101011100111
```

## Go on a standard 19 × 19 board

A094777
 (19)
Number of legal positions in Go played on an
 19 × 19
grid (each group must have at least one liberty).[2]
 212667732900366224249789357650440598098805861083269127196623872213228196352455447575029701325
A007565 Number of Go games with
 n
moves.
 {1, 362, 130683, 47046243, 16889859363, 6046709375131, ...}
A048289 Number of Go games with exactly
 n
moves.
 {1, 361, 130321, 46915560, 16842813120, 6029819515768, ...}
A089071 Number of liberties a big eye of size
 n
gives in the game of Go.
 {1, 2, 3, 5, 8, 12, 17, 23, 30, 38, 47, 57, 68, 80, 93, 107, 122, 138, 155, 173, 192, 212, 233, 255, 278, 302, 327, 353, 380, 408, 437, 467, 498, 530, 563, 597, 632, 668, ...}

## Go on a n × n board

A094777 Number of legal positions in Go played on an
 n × n
grid (each group must have at least one liberty).[2]
 {1, 57, 12675, 24318165, 414295148741, 62567386502084877, 83677847847984287628595, 990966953618170260281935463385, ...}
A242709 Nonequivalent ways to place two different markers (e.g., a pair of Go stones, black and white) on an
 n × n
grid.
 {0, 2, 12, 33, 85, 165, 315, 518, 846, 1260, 1870, 2607, 3627, 4823, 6405, 8220, 10540, 13158, 16416, 20045, 24465, 29337, 35167, 41538, 49050, 57200, 66690, 76923, 88711, ...}

## Abstract games of Go

### Go on a 1 × n board

A102620 Number of legal Go positions on a
 1 × n
board (for which
 3 n
is a trivial upper bound).
 {1, 5, 15, 41, 113, 313, 867, 2401, 6649, 18413, 50991, 141209, 391049, 1082929, 2998947, 8304961, 22998865, 63690581, 176377839, 488441801, 1352638145, 3745850473, 10373355075, ...}
A096259 Longest period of an abstract version of the game of Go on a
 1 × n
board.
 {1, 2, 6, 24, 70, 180, 294, 112, 270, 900, 330, 792, ...}

### Go on a 2 × n board

A266278 Number of legal Go positions on a
 2 × n
board.
{5, 57, 489, 4125, 35117, 299681, 2557605, 21826045, 186255781, 1589441093, 13563736693, 115748216413, 987755062201, 8429158472781, 71931509371765, 613838505628281, ...}