OFFSET
1,2
COMMENTS
These counts have not been reduced to take into account the symmetries of the board.
REFERENCES
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.
EXAMPLE
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.
CROSSREFS
KEYWORD
nonn
AUTHOR
Don Knuth, Mar 26 2008
EXTENSIONS
a(1) and a(7) corrected and a(11)-(15) added by Tomas Rokicki, Oct 29 2010
STATUS
approved