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Search: id:A023999
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| A023999 |
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Absolute value of determinant of n X n matrix whose entries are the integers from 1 to n^2 spiraling inward, starting in a corner. |
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+0
3
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| 1, 5, 48, 660, 11760, 257040, 6652800, 198918720, 6745939200, 255826771200, 10727081164800, 492775291008000, 24610605962342400, 1327677426915840000, 76940526008586240000, 4766815315895592960000, 314406967644177408000000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Starting in the NW or SE corner, the signs are cyclic (+,-,-,+), starting in the NE or SW corner, the signs are always positive.
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REFERENCES
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Problem 1517 in the Feb. 1997 issue of Mathematics Magazine.
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FORMULA
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a(n) = (-1)^((n+4)(n-1))/2 *(3n-1) * (2n-3)!/(n-2)!.
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EXAMPLE
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n=4: det of
.1..2..3.4
12.13.14.5
11.16.15.6
10..9..8.7
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CROSSREFS
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Cf. A079340, A078475, A067276, A052182.
Sequence in context: A086776 A116431 A048435 this_sequence A126224 A108207 A127091
Adjacent sequences: A023996 A023997 A023998 this_sequence A024000 A024001 A024002
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KEYWORD
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nonn
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AUTHOR
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Charles Diminnie (charles.diminnie(AT)rampo.angelo.edu)
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgw(AT)rgwv.com), May 07 2003
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