A050944 Numbers k such that sigma(k) > sigma(k+1) > sigma(k+2) > sigma(k+3).
44, 104, 116, 164, 224, 272, 296, 344, 356, 464, 512, 560, 584, 620, 704, 776, 824, 836, 860, 884, 1004, 1112, 1184, 1196, 1280, 1304, 1424, 1484, 1520, 1544, 1592, 1616, 1700, 1724, 1880, 1904, 1952, 1964, 2024, 2036, 2120, 2144, 2276, 2324, 2372, 2384, 2444
Offset: 1
Keywords
Examples
sigma(44)=84 > sigma(45)=78 > sigma(46)=72 > sigma(47)=48.
References
- David Wells, The Penguin Dictionary of Curious and Interesting Numbers, entry 44.
Links
- Seiichi Manyama, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Position[Partition[DivisorSigma[1,Range[2500]],4,1],?(Max[ Differences[ #]]<0&),1,Heads->False]//Flatten (* _Harvey P. Dale, Sep 13 2020 *)
Extensions
Name simplified by Sean A. Irvine, Aug 20 2021