

A006983


Number of simple perfect squared squares of order n up to symmetry.
(Formerly M4482)


29



0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 8, 12, 26, 160, 441, 1152, 3001, 7901, 20566, 54541, 144161, 378197, 990981, 2578081, 6674067, 17086918
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OFFSET

1,22


COMMENTS

A squared rectangle (which may be a square) is a rectangle dissected into a finite number of two or more squares. If no two squares have the same size, the squared rectangle is perfect. A squared rectangle is simple if it does not contain a smaller squared rectangle. The order of a squared rectangle is the number of constituent squares.  Geoffrey H. Morley, Oct 17 2012


REFERENCES

J.P. Delahaye, Les inattendus mathématiques, BelinPour la Science, Paris, 2004, pp. 9596.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Gunnar Brinkmann and Brendan McKay, plantri and fullgen programs for generation of certain types of planar graph.
Gunnar Brinkmann and Brendan McKay, plantri and fullgen programs for generation of certain types of planar graph [Cached copy, pdf file only, no active links, with permission]
A. J. W. Duijvestijn, Illustration for a(21)=1 (The unique simple squared square of order 21. Reproduced with permission of the discoverer.)


CROSSREFS



KEYWORD

nonn,hard,more,nice


AUTHOR



EXTENSIONS

Leading term changed from 0 to 1, Apr 15 1996
Leading term changed back to 0, Dec 25 2010 (cf. A178688)
a(29) changed to 7901, identified a duplicate tiling in order 29.  Stuart E Anderson, Jan 07 2012
a(28) changed to 3000, identified a duplicate tiling in order 28.  Stuart E Anderson, Jan 14 2012
a(28) changed back to 3001 after a complete recount of order 28 SPSS recalculated from cnets with cleansed data, established the correct total of 3001.  Stuart E Anderson, Jan 24 2012


STATUS

approved



