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A136278 Number of n X n Life configurations that are "still Life"s (unchanged in one step). 2

%I

%S 1,2,12,83,417,3928,127425,4782725,285886827,29305144137,

%T 5078448221965,1689709601427846,898792333612812818,

%U 812773906928265250254,1327574905899625395329686

%N Number of n X n Life configurations that are "still Life"s (unchanged in one step).

%C These counts have not been reduced to take into account the symmetries of the board.

%D E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982; see Chapter 25.

%D D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.

%e 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.

%Y Cf. A134963, A136279, A136280.

%K nonn

%O 1,2

%A _Don Knuth_, Mar 26 2008

%E a(1) and a(7) corrected and a(11)-(15) added by _Tomas Rokicki_, Oct 29 2010

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Last modified May 21 06:36 EDT 2022. Contains 353889 sequences. (Running on oeis4.)