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Search: id:A136278
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| A136278 |
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Number of n X n Life configurations that are "still Life"s (unchanged in one step). |
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+0
3
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| 2, 2, 12, 83, 417, 3928, 58697, 4782725, 285886827, 29305144137
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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These counts have not been reduced to take account of the symmetries of the board.
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REFERENCES
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E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982; see Chapter 25.
D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.
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EXAMPLE
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The 83 still lifes for n=4 have well-known names, explained in the book by Berlekamp et al: 9 are blocks, 12 are snakes, 4 are tubs, 16 are boats, 8 are ships, 8 are aircraft carriers, 4 are beehives, 8 are eaters, 4 are loaves, 2 are barges, 4 are longboats, 2 are long barges, 1 is the pond and the other one is empty.
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CROSSREFS
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Cf. A134963, A136279, A136280.
Sequence in context: A013315 A032321 A013311 this_sequence A087220 A032320 A032227
Adjacent sequences: A136275 A136276 A136277 this_sequence A136279 A136280 A136281
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KEYWORD
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nonn
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AUTHOR
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D. E. Knuth, Mar 26 2008
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