

A162280


Second numbers with the same values for sigma_0(n) and sigma(n) as one or more other numbers.


4



15, 35, 51, 69, 95, 56, 115, 70, 143, 145, 155, 159, 110, 177, 135, 205, 235, 154, 265, 287, 195, 140, 295, 184, 329, 231, 335, 377, 355, 238, 325, 339, 413, 266, 415, 286, 220, 473, 445, 497, 310, 533, 447, 589, 583, 374, 501, 455, 308, 565, 537, 376, 270
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OFFSET

1,1


COMMENTS

Numbers n such that for exactly one m < n, sigma(n) = sigma(m) and sigma_0(n) = sigma_0(m). There may be more such m > n.
The associated m values are in A162279.
See the afile for a PARI program and more values.


LINKS

Table of n, a(n) for n=1..53.
Franklin T. AdamsWatters, Table of duplicate sigma values up to sigma(n) = 10000


EXAMPLE

sigma(14) = sigma(15) = 24, sigma_0(14) = sigma_0(15) = 4, so 15 is in the sequence. sigma(16) = sigma(25) = 31, but sigma_0(16) = 5 != sigma_0(25) = 3, so 25 is not in the sequence


CROSSREFS

Cf. A000005, A000203, A162279, A162281, A162282, A162283.
Sequence in context: A108668 A201018 A187400 * A290781 A063532 A212331
Adjacent sequences: A162277 A162278 A162279 * A162281 A162282 A162283


KEYWORD

nonn


AUTHOR

Franklin T. AdamsWatters, Jun 29 2009


STATUS

approved



