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A072843 O'Halloran numbers: even integers which cannot be the surface area of a cuboid with integer-length sides. 0
8, 12, 20, 36, 44, 60, 84, 116, 140, 156, 204, 260, 380, 420, 660, 924 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Named to commemorate the founder of the Australian Mathematics Competition, Peter O'Halloran, shortly before his untimely death in 1994.

REFERENCES

A. Edwards - "The Cellars At The Hotel Mathematics" - Keynote article in "Mathematics - Imagine The Possibilities" (Conference handbook for the MAV conference - 1997) pp. 18-19

LINKS

Table of n, a(n) for n=0..15.

EXAMPLE

The total surface areas of the smallest possible cuboids (1.1.1), (2.1.1),(2.2.1),(3.1.1) and (4.1.1) are, respectively, 6, 10, 16, 14 and 18 square units, assuming their side lengths are whole numbers. Thus the first two O'Halloran Numbers are 8 and 12 as they do not appear on this list of areas.

CROSSREFS

Sequence in context: A211410 A001749 A175786 * A072902 A189322 A105571

Adjacent sequences:  A072840 A072841 A072842 * A072844 A072845 A072846

KEYWORD

fini,full,nonn

AUTHOR

Andy Edwards (AndynGen(AT)aol.com), Jul 24 2002

STATUS

approved

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Last modified November 22 10:40 EST 2014. Contains 249805 sequences.