This site is supported by donations to The OEIS Foundation.



Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A261798 Maximum water retention of an associative magic square of order n. 2
0, 0, 0, 15, 59, 0, 361, 704, 1247, 0 (list; graph; refs; listen; history; text; internal format)



Two of the most famous magic squares are associative magic squares - the Lo Shu magic square and Dürer's magic square. Al Zimmermann's programing contest in 2010 produced the presently known maximum retention values for magic squares order 4 to 28 A201126. No concerted effort has been made to find the maximum retention for associative magic squares.

There are 4211744 different water retention patterns for a 7 x 7 square A054247 and 1.12*10^18 different order 7 associative magic squares. There is no proof that the presently stated maximum retention values greater than order 5 are actually the maximum possible retention.

a(11) >= 3226, a(12) >=4840, a(13) >= 6972.

The Goo Wikipedia associative magic square link below shows the first attempt to classify a set of data by its water retention. Here the 48 associative order 4 magic squares are thus classified. Perhaps there might be some correlation between this surface evaluation and Mohs hardness scale.


Table of n, a(n) for n=1..10.

Goo Wikipedia, Associative magic square.

Craig Knecht, Order 5 associative magic square.

Craig Knecht, Order 7 associative magic square.

Craig Knecht, Order 8 associative magic square.

Craig Knecht, Order 9 associative magic square.

Craig Knecht, Order 12 associative magic square.

Johan Ofverstedt, Water Retention on Magic Squares with Constraint Based Local Search.

Wikipedia, Magic square construction and Water retention on mathematical surfaces.


(16  3  2  13)

(5  10 11   8)

(9   6  7  12)

(4  15  14  1)

This is Albrecht Dürer's famous magic square in Melencolia I. Dürer put the date of its creation (1514) in the numbers in the bottom row. This square holds 5 units of water.


Cf. A201126 (water retention on magic squares), A201127(water retention on semi-magic squares), A261347 (water retention on number squares).

Sequence in context: A183942 A012691 A020187 * A022287 A288747 A223344

Adjacent sequences:  A261795 A261796 A261797 * A261799 A261800 A261801




Craig Knecht, Sep 01 2015



Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 14 09:49 EST 2018. Contains 318095 sequences. (Running on oeis4.)