

A188486


Numbers n such that abundance(n) is an odd square.


3



550564, 15038884, 57365476, 197686728, 257859364, 1027291978962, 4644774970276, 319916794343524, 694453849937352, 97695446432293264, 359108743507594276
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OFFSET

1,1


COMMENTS

Counterexamples to the Kravitz conjecture. Subsequence of A188484 with positive abundances. Abundances are A188488, sigma(n)  2n.


LINKS

Table of n, a(n) for n=1..11.
Eric Weisstein's World of Mathematics, Kravitz Conjecture


CROSSREFS

Cf. A188484, A188488.
Sequence in context: A251035 A236827 A077456 * A204571 A253614 A249687
Adjacent sequences: A188483 A188484 A188485 * A188487 A188488 A188489


KEYWORD

nonn,hard


AUTHOR

Eric W. Weisstein, Apr 01 2011


EXTENSIONS

a(4), a(5) from D. S. McNeil, Apr 02 2011
a(6)  a(8) from Jack Brennen, May 03 2011
a(9) from Jack Brennen and Charles R Greathouse IV, May 04 2011
a(10)a(11) from Charles R Greathouse IV, May 04, 2011


STATUS

approved



