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Search: id:A076773
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| A076773 |
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2-nadirs of phi: n such that phi(n-2) > phi(n-1) > phi(n) < phi(n+1) < phi(n+2). |
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1
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| 315, 525, 735, 1155, 1365, 1575, 1755, 1785, 1815, 1995, 2145, 2415, 2475, 2805, 3045, 3315, 3465, 3885, 4095, 4125, 4305, 4515, 4725, 4935, 5115, 5145, 5355, 5775, 6045, 6195, 6405, 6435, 6615, 6825, 7035, 7095, 7245, 7395, 7455, 7605, 7665, 8085
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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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).
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EXAMPLE
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phi(313), ..., phi(317) equal 312, 156, 144, 156, 316, respectively, so 315 is a 2-nadir of phi(n).
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MATHEMATICA
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Select[Range[3, 10^4], EulerPhi[ # - 2] > EulerPhi[ # - 1] > EulerPhi[ # ] < EulerPhi[ # + 1] < EulerPhi[ # + 2] &]
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CROSSREFS
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Sequence in context: A157621 A104819 A076648 this_sequence A114807 A109130 A087415
Adjacent sequences: A076770 A076771 A076772 this_sequence A076774 A076775 A076776
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 14 2002
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