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Magic Constant


The magic constant of a normal magic square of order n is the common sum of its rows, columns, and main diagonals. Since its entries are the integers 1, 2, ..., n^2, this sum is

M_2(n)=1/nsum_(k=1)^(n^2)k
(1)
=1/2n(n^2+1).
(2)

The first few values are 1, 5, 15, 34, 65, 111, 175, 260, ... (OEIS A006003). The magic constant for an nth order magic square starting with an integer A and with entries in an increasing arithmetic series with difference D between terms is

 M_2(n;A,D)=1/2n[2A+D(n^2-1)]
(3)

(Hunter and Madachy 1975, Madachy 1979). In a panmagic square, in addition to the main diagonals, the broken diagonals also sum to M_2(n).

For a magic cube, magic tesseract, etc., the magic d-D constant is

M_d(n)=1/(n^(d-1))sum_(k=1)^(n^d)k
(4)
=1/2n(n^d+1).
(5)

The first few magic constants are summarized in the following table.

nM_2(n)M_3(n)M_4(n)
SloaneA006003A027441A021003
1111
25917
31542123
434130514
5653151565

There is a corresponding multiplicative magic constant for multiplication magic squares.

A similar magic constant M_n^((k)) of degree k is defined for magic series and multimagic series as 1/n times the sum of the first n^2 kth powers,

M_n^((k))=1/nsum_(i=1)^(n^2)i^k
(6)
=(H_(n^2)^((-k)))/n,
(7)

where H_n^((k)) is a harmonic number of order k. The following table gives the first few values.

nk=1k=2k=3k=4
SloaneA006003A052459A052460A052461
11111
251550177
315956755111
434374462460962
565110521125430729

See also

Magic Cube, Magic Geometric Constants, Magic Hexagon, Magic Series, Magic Square, Multimagic Series, Multiplication Magic Square, Panmagic Square

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References

Hunter, J. A. H. and Madachy, J. S. "Mystic Arrays." Ch. 3 in Mathematical Diversions. New York: Dover, pp. 23-34, 1975.Madachy, J. S. Madachy's Mathematical Recreations. New York: Dover, p. 86, 1979.Pickover, C. A. The Zen of Magic Squares, Circles, and Stars: An Exhibition of Surprising Structures across Dimensions. Princeton, NJ: Princeton University Press, 2002.Sloane, N. J. A. Sequences A006003/M3849, A021003, A027441, A052459, A052460, and A052461 in "The On-Line Encyclopedia of Integer Sequences."

Referenced on Wolfram|Alpha

Magic Constant

Cite this as:

Weisstein, Eric W. "Magic Constant." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/MagicConstant.html

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