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A317575
Irregular triangle read by rows: T(n,k) is the number of n X n tic-tac-toe positions (up to rotation and reflection) with k tokens (i.e., after k plays) which occur in a game (n > 0, 0 <= k <= n^2).
3
1, 1, 1, 1, 2, 2, 0, 1, 3, 12, 38, 108, 174, 204, 153, 57, 15, 1, 3, 33, 219, 1413, 5514, 20122, 50215, 112379, 179510, 245690, 245690, 193318, 110452, 41870, 10489, 1059, 1, 6, 85, 904, 9664, 66859
OFFSET
1,5
EXAMPLE
Triangle begins:
n\k | 0 1 2 3 4 5 6 7 8 9
----+---------------------------------------
1 | 1 1
2 | 1 1 2 2 0
3 | 1 3 12 38 108 174 204 153 57 15
CROSSREFS
Cf. A008907 (3rd row), A008805 (column k=1), A242709 (column k=2), A317573, A317574.
Sequence in context: A292913 A214776 A369415 * A295653 A146326 A276727
KEYWORD
nonn,tabf,more
AUTHOR
Álvar Ibeas, Jul 31 2018
STATUS
approved