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A188483
Numbers whose squares have an odd square abundance
0
742, 3878, 7574, 16058, 2155174, 17886218, 312562708, 599256826, 5015867878, 6305036122, 7661332826
OFFSET
1,1
COMMENTS
Kravitz conjectured that no numbers exist whose abundance is a positive odd square. The squares of this sequence are counterexamples.
a(12) <= 37379475098. a(13) <= 56559884906. - Donovan Johnson, Apr 07 2011
REFERENCES
Guy, R. K. Unsolved Problems in Number Theory, 3rd ed. New York: Springer-Verlag, 2004, page 74.
CROSSREFS
Sequence in context: A319043 A044984 A252576 * A235675 A235445 A349677
KEYWORD
nonn,hard,more
AUTHOR
Ed Pegg Jr, Apr 01 2011
EXTENSIONS
More terms, page number in Guy, cross references.
a(9)-a(11) from Donovan Johnson, Apr 07 2011
STATUS
approved