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A375859
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In an n X n grid draw straight walls between cells, starting at a border, such that the resulting figure is connected and has only one-cell wide paths; a(n) is the number of solutions up to rotations.
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0
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1, 1, 17, 278, 6299, 151928, 3980838, 112842972, 3477284215, 116563600340, 4243245979546, 167133229071276, 7090692397872054, 322501848961962040, 15654927191595331100, 807745569550956567160, 44138380646154800057431, 2546015709192980766909132, 154576479598442363146107882
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OFFSET
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1,3
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COMMENTS
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LINKS
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EXAMPLE
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a(3) = 17. The A375770(3) = 10 distinct solutions with their multiplicities are:
._._._. ._._._. ._._._. ._._._. ._._._.
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(1) (2) (2) (1) (2)
._._._. ._._._. ._._._. ._._._. ._._._.
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(2) (2) (2) (1) (2)
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PROG
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(PARI) \\ See PARI link in A375770 for program code.
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CROSSREFS
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Cf. A375770 (up to rotations and reflections), A375817 (not reduced for symmetry), A375860 (up to symmetries of rectangle).
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KEYWORD
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nonn,new
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AUTHOR
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STATUS
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approved
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