Additive-Multiplicative Magic Square


This page describes the magic square which is simultaneously a magic square and multiplicative magic square.

Multiplicative magic square

Multiplicative magic square is a square which is magic using multiplication instead of addition. It is not so difficult, using powering to make this type of square. Following is order 3 example.
P = 4096 (= 212)
23 28 21
22 24 26
27 20 25

Some square that satisfy simultaneously magic sum and magic multiply. Today (May 2006), I know order 8 and order 9 are constructed, but other order squares are unknown. Belows are current status.


Order 3 : Impossible

Folloing is order-3 basic magic square.
a b c
d e f
g h i

The conditions of magic square provide the following equations.
    b + c = d + g c (1)
    b * c = d * g c (2)
b=d or b=g is solution which is satisfied both (1) and (2), those conditions don't satisfy the condition of magic square. Then, non normal order-3 bimagic square cannot exist.


Order 4 : Impossible

Each element of order-4 magic square describe a11`a44.
a11 a12 a13 a14
a21 a22 a23 a24
a31 a32 a33 a34
a41 a42 a43 a44
The conditions of magic square provide the following equations.
    a11 + a12 + a13 + a14 = S ... (1)
On order 4 square, sum of corner is the constant (proof ellipsis),
    a11 + a14 + a41 + a44 = S ... (2)
(1)-(2)
    a12 + a13 = a41 + a44 ... (3)
Same conditions can apply to squared number,
    a12 * a13 = a41 * a44 ... (4)
When we solve (3) and (4), we have following equation.
a12 = a41 or a44
Those condtions don't satisfy the condition of magic square. Then, non normal order 4 bimagic square cannot exist.


Order 5 : Unknown

Order 5 additive-multiplicative magic square exeistance is unknown.


Order 6 : Unknown

Order 6 additive-multiplicative magic square exeistance is unknown. Following is possible to have all multiplicative and some additive properties.

2005: Order 6 multiplicative square with 6 additive-multiplicative rows< by Christian Boyer
S (row only) = 173
P = 39,916,800
  (=2^8*3^4*5^2*7*11)
Max number = 88
1 33 36 48 35 20
54 55 2 10 24 28
50 14 72 22 12 3
88 16 30 7 5 27
8 6 70 60 18 11
21 15 4 9 44 80


Order 7 : Unknown

Order 7 additive-multiplicative magic square exeistance is unknown. Following is possible to have all multiplicative and some additive properties.

2005: Order 7 multiplicative square with 7 additive-multiplicative rows by Christian Boyer
S (row only) = 238
P = 3,632,428,800
  (=2^8*3^4*5^2*7^2*11*13)
Max number = 91
35 48 1 39 40 33 42
77 65 20 16 36 3 21
4 56 54 7 26 25 66
9 14 44 24 6 91 50
52 5 70 63 22 18 8
12 11 84 10 15 28 78
60 27 13 55 49 32 2


Order 8 : Possible

First order 8 square is constructed by Walter H. Horner (1955).
1955: Order 8 additive-multiplicative magic square, by Walter H. Horner,
S = 840
P = 2,058,068,231,856,000
  (=2^7*3^8*5^3*7*13*17*19*23*29)
Max number = 261
46 81 117102 15 76 200203
1960232175 546915378
2161611752 171905875
1351145087 1841891368
1502614538 911369227
11910410823 1742255730
11625133120 5126162207
3934138243 10029105152

In November 2005, Christian Boyer constructed better order 8 additive-multiplicative squares with smaller constants.
2005: Order 8 additive-multiplicative magic square, by Christian Boyer
S = 760
P = 51,407,948,592,000
  (=2^7*3^6*5^3*7^2*11*13*17*37)
Max number = 333
22266 22563 5 7 68104
1 35 52 136 19874 18975
13229621 175 9 15 78 34
45310226 14826425147
51117106 2008425933
16810023137 39153230
9117820 4215099333
50126111297 11913404

2005: Order 8 additive-multiplicative magic square, by Christian Boyer
S = 600
P = 67,463,283,888,000
  (=2^7*3^4*5^3*7^2*11*13*17*19*23)
Max number = 225
7538 207102 11 20 9156
5 44 49 104 5750 153138
13320017 92 45 66 21 26
99303914 1751522368
78632215 18411910019
1361617625 421171033
28134077 3469114225
4651150171 5278835


Order 9 : Possible

First order 9 square is constructed by Horner and Madachy (1975).
1952: Order 9 additive-multiplicative magic square, by Walter H. Horner,
S = 848
P = 5,804,807,833,440,000
  (=2^8*3^7*5^4*7*11*17*19*23*29)
Max number = 290
20087954299 146108170
14441018481 8515026119
1382431750116 19056335
5712523297 666823054
4702251115 21617125174
1532316276250 5833588
14515275116 632703492
110228135136 6929114225
2710220729038 10055821

In November 2005, Christian Boyer constructed better order 9 additive-multiplicative squares with smaller constants.

2005: Order 9 additive-multiplicative magic square, by Christian Boyer
S = 784
P = 2,987,659,715,040,000
  (=2^8*3^4*5^4*7*11*13*17*19*23*31)
Max number = 310
38150248107 654415369
4633922102 18419025155
1101711576225 93242104
18615250135 702073368
11732813888 343195250
235517027957 10078814
2006211435130 1519299
2152913646 6612531019
852301175124 17156266

2005: Order 9 additive-multiplicative magic square, by Christian Boyer
S = 840
P = 7,349,391,483,033,600
  (=2^11*3^7*5^2*7^2*11*13*17*19*29)
Max number = 261
841451338011 610424334
4099278135 11922429114
20827102112261 3830557
9519687160 8815352108
9204485182 8119168232
1715621617156 11657033
20357140668 105468234
2249018951 13017415228
162136265876 25277350


Order 16 : Possible

In December 2008, first order 16 square is constructed by Mohamad Moosavi.
2008: Order 16 additive-multiplicative magic square, by Mohamad Moosavi
S = 8432
P = 5,520,657,501,700,315,221,083,892,340,123,238,400,000
  (= 2^24*3^13*5^5*7^3*11*13*17*19*23*37*41*43*53*67*71*103*107)
Max number = 1968
1634922069621005800798460749256102729583516710
2464123217009121110871192136644535430852891477
3091234248556509381184119160642736781387530972
8421033691072103674175085655285224636810639473
4053713444268281177384170742012001141331519681442
2585685672653202041012963100228222671722164815273
49721531864818728810701104171501342961545159929416
4244863553011284920153352268148571503361413391845
666737600570514798461810537956889949232112834
5006848146037388247105602113612156896468276107
6274506708887216151268106555974212965132214368
804740513550168651586184811349236454281841796
1196160551223881159172142923114761030370469400342
4482721380139186284243531230123611189300456518335
25541614981472213431063241133110721012399250402592
1712128822148021216271129252109271353536444285350


Other order 10 and upper : Unknown

I think 10 and upper squares may exist.


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