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A065015
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Sum divides product: number of integer solutions (w,x,y,z), w>=x>=y>=z>0, to the equation w*x*y*z = n*(w+x+y+z).
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0
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1, 5, 4, 8, 6, 14, 7, 15, 12, 22, 7, 26, 9, 24, 23, 30, 8, 42, 11, 31, 21, 29, 12, 56, 18, 32, 27, 48, 13, 68, 11, 42, 35, 40, 32, 65, 9, 35, 30, 76, 9, 87, 18, 51, 49, 39, 18, 97, 27, 70, 31, 52, 14, 108, 36, 72, 33, 52, 17, 120, 15, 37, 66, 90, 36, 93, 12, 63, 44, 123, 19, 130
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| See A063520 for the corresponding problem in three variables.
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EXAMPLE
| a(7)=7, since there are seven such solutions to wxyz=7(w+x+y+z): (42,2,2,2), (49,4,2,1), (7,4,4,1), (10,7,2,1), (70,8,1,1), (28,10,1,1) and (16,14,1,1).
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CROSSREFS
| A063520.
Sequence in context: A003672 A081818 A023848 * A002340 A023845 A051555
Adjacent sequences: A065012 A065013 A065014 * A065016 A065017 A065018
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KEYWORD
| nonn
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AUTHOR
| John W. Layman (layman(AT)math.vt.edu), Nov 01 2001
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