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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
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: A001749 A175786 A258848 * A354069 A350615 A300065
KEYWORD
fini,full,nonn
AUTHOR
Andy Edwards (AndynGen(AT)aol.com), Jul 24 2002
STATUS
approved

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)