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A076774 2-nadirs of sigma: n such that sigma(n-2) > sigma(n-1) > sigma(n) < sigma(n+1) < sigma(n+2). 0
17254, 27754, 68914, 69686, 82774, 92366, 111266, 133706, 152426, 194426, 267994, 277586, 359974, 387694, 389726, 429274, 448174, 452726, 457766, 471626, 474146, 522026, 527066, 531334, 554126, 567386, 595594, 610226, 674246, 674974 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

I call n a "k-nadir" (or nadir of depth k) of the arithmetical function f if n satisfies f(n-k) > ... > f(n-1) > f(n) < f(n+1) < ... < f(n+k).

LINKS

Table of n, a(n) for n=1..30.

MATHEMATICA

Select[Range[3, 10^6], DivisorSigma[1, # - 2] > DivisorSigma[1, # - 1] > DivisorSigma[1, # ] < DivisorSigma[1, # + 1] < DivisorSigma[1, # + 2] &]

CROSSREFS

Sequence in context: A233993 A043621 A293478 * A236447 A094413 A209967

Adjacent sequences:  A076771 A076772 A076773 * A076775 A076776 A076777

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Nov 14 2002

STATUS

approved

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Last modified October 18 04:46 EDT 2019. Contains 328145 sequences. (Running on oeis4.)