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A317401 Number of distinct (up to rotation and reflection) tic-tac-toe positions with n tokens which allow a winning strategy for X. 2
0, 0, 7, 9, 85, 67, 139, 70, 23, 12 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Including positions where X has already won (that is, 0 for even n, A048245(n) for odd n up to 7, and 12 for n = 9).

LINKS

Table of n, a(n) for n=0..9.

Index entries for sequences related to tic-tac-toe

EXAMPLE

a(2) = 7:

x o .   x . o   x . .   x . .   . x .   . x .   . o .

. . .   . . .   . . o   . . .   o . .   . . .   . x .

. . .   . . .   . . .   . . o   . . .   o . .   . . .

CROSSREFS

Cf. A008907, A317402, A048245.

Sequence in context: A087336 A178427 A285011 * A137058 A116237 A123746

Adjacent sequences:  A317398 A317399 A317400 * A317402 A317403 A317404

KEYWORD

fini,full,nonn

AUTHOR

Álvar Ibeas, Jul 27 2018

STATUS

approved

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Last modified August 15 16:02 EDT 2020. Contains 336505 sequences. (Running on oeis4.)