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Number of n-dimensional cuboids with integral edge lengths for which volume = surface area.
4

%I #34 Jan 18 2020 07:38:14

%S 2,10,108,2892,270332

%N Number of n-dimensional cuboids with integral edge lengths for which volume = surface area.

%C For n>1 it is always true that a(n) > 0 because for dimension n we always have the n-dimensional cuboid with all edge lengths = 2n = A062971(n) having hypervolume (2n)^n equal to "surface hyper-area". - _Jonathan Vos Post_, Mar 15 2006

%C Number of nondecreasing tuples (x_1, x_2, ..., x_n) such that 1/2 = 1/x_1 + 1/x_2 + ... + 1/x_n. - _Lewis Chen_, Dec 20 2019

%H Gerald E. Gannon, Martin V. Bonsangue and Terrence J. Redfern, <a href="http://www.jstor.org/stable/27970109">One Good Problem Leads to Another and Another and...</a>, Math. Teacher, 90 (#3, 1997), pp. 188-191.

%H Michel Marcus, <a href="/A003167/a003167.txt">Cuboids for n=4</a>, after Joseph Myers.

%e From _Joseph Myers_, Feb 24 2004: (Start)

%e For n=2 the cuboids are 3 X 6 and 4 X 4.

%e For n=3 the cuboids are 3 X 7 X 42, 3 X 8 X 24, 3 X 9 X 18, 3 X 10 X 15, 3 X 12 X 12, 4 X 5 X 20, 4 X 6 X 12, 4 X 8 X 8, 5 X 5 X 10, 6 X 6 X 6. (End)

%e For n=4 see the Marcus link.

%Y Cf. A002966.

%K nonn,hard,more

%O 2,1

%A mjzerger(AT)adams.edu

%E a(5)-a(6) from _Joseph Myers_, Feb 24 2004