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A129947 Smallest possible side length for a simple perfect squared square of order n; or 0 if no such square exists. 5
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 112, 110, 110, 120, 147, 212, 180, 201, 221, 201, 215, 185 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,21

COMMENTS

It is not known whether this sequence is the same as sequence A217148. It may be that A129947(33) = 246 and A217148(33) = 234. - Geoffrey H. Morley, Jan 10 2013

From Geoffrey H. Morley, Oct 17 2012: (Start)

A squared rectangle (which may be a square) is a rectangle dissected into a finite number, two or more, of squares. If no two of these squares have the same size the squared rectangle is perfect. The order of a squared rectangle is the number of constituent squares.

A squared rectangle is simple if it does not contain a smaller squared rectangle.

The smallest known sides of simple perfect squared squares (and the known orders of the squares) are 110 (22, 23), 112 (21), 120 (24), 139 (22, 23), 140 (23), 145 (23), 147 (22, 25) ...

The upper bounds shown below for n = 33-38 and 40-44 are from J. B. Williams. The rest are from Gambini's thesis. - Geoffrey H. Morley, Mar 08 2013

======================================

Upper bounds for a(n) for n = 31 to 59

======================================

   |  +0   +1   +2   +3   +4   +5   +6   +7   +8   +9

======================================================

30 |   -    -    -   246  315  276  341  319  352  360

40 |  328  336  360  413  425  543  601  691  621  779

50 |  788  853    ?  824  971  939  929  985 1100 1060

======================================================

(End)

LINKS

Table of n, a(n) for n=1..32.

S. E. Anderson, Perfect Squared Rectangles and Squared Squares.

Stuart Anderson, 'Special' Perfect Squared Squares", accessed 2014. - N. J. A. Sloane, Mar 30 2014

I. Gambini, Quant aux carres carreles, Thesis, Universite de la Mediterranee Aix-Marseille II, 1999, pp. 73-78.

Eric Weisstein's World of Mathematics, Perfect Square Dissection

Index entries for squared squares

CROSSREFS

Cf. A006983, A174386, A181735, A217148, A217149, A217156.

Sequence in context: A010032 A190026 * A217148 A223822 A262521 A096680

Adjacent sequences:  A129944 A129945 A129946 * A129948 A129949 A129950

KEYWORD

nonn,hard,more

AUTHOR

Alexander Adamchuk, Jun 09 2007, corrected Jun 11 2007

EXTENSIONS

Unproved statement misattributed to Skinner replaced, known upper bounds corrected, and crossref added by Geoffrey H. Morley, Mar 19 2010

Additional term added, initial term a(0)=1 deleted by Stuart E Anderson, Dec 26 2010

Upper bounds for terms a(31) to a(78), (all from Ian Gambini's thesis) added by Stuart E Anderson, Jan 20 2011

New bound for a(29)<=221, from Stuart E Anderson & Ed Pegg Jr, Jan 20 2011

a(29) confirmed as 221, from Stuart E Anderson, Ed Pegg Jr, and Stephen Johnson, Aug 22 2011

New bound for a(31)<=236, computed by Stephen Johnson in September 2011, updated by Stuart E Anderson, Oct 04 2011

a(30) from Stuart E Anderson and Lorenz Milla added by Geoffrey H. Morley, Jun 15 2013

a(31) and a(32) from Lorenz Milla and Stuart E Anderson, Oct 05 2013

STATUS

approved

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Last modified May 27 10:03 EDT 2017. Contains 287204 sequences.