A162279 Minimal numbers with the same values for sigma_0(n) and sigma(n) as one or more other numbers.

14, 33, 46, 62, 87, 54, 94, 66, 123, 118, 141, 142, 102, 158, 114, 166, 213, 138, 214, 249, 182, 132, 267, 174, 254, 186, 303, 278, 321, 230, 244, 302, 395, 248, 334, 246, 204, 393, 358, 382, 282, 485, 398, 553, 535, 318, 446, 429, 276, 454, 478, 354, 264

Offset

1,1

Comments

Numbers n such that for some m > n, sigma(n) = sigma(m) and sigma_0(n) = sigma_0(m), but this does hold for any m < n.

Values are sorted by sigma(n), then by sigma_0(n).

See the a-file for a PARI program and more values.

Links

Table of n, a(n) for n=1..53.

Franklin T. Adams-Watters, Table of duplicate sigma values up to sigma(n) = 10000

Example

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

Crossrefs

Cf. A000005, A000203, A162280, A162281, A162282, A162283.

Sequence in context: A250186 A191676 A191866 * A367346 A090090 A116150

Adjacent sequences: A162276 A162277 A162278 * A162280 A162281 A162282

Keyword

nonn

Author

Franklin T. Adams-Watters, Jun 29 2009

Status

approved