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A050945
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Numbers k such that sigma(k) > sigma(k+1) > sigma(k+2) > sigma(k+3) > sigma(k+4) > sigma(k+5).
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3
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20021154, 28503474, 53728674, 224539314, 242917674, 304178874, 341295954, 370845474, 377692314, 443998554, 533007474, 610484874, 709445274, 855529674, 964885074, 978052074, 1069943874, 1114988874, 1167961794
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OFFSET
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1,1
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COMMENTS
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There are many examples of 4 consecutive numbers having decreasing values of sigma (see cross references) and there are 83 cases of 6 consecutive numbers with decreasing values of sigma < 4,293,000,000. Interestingly (and for unknown reasons) there are no examples of exactly 5 such consecutive numbers in that range! All known members of the sequence are multiples of 6 and one less than a multiple of 35.
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REFERENCES
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David Wells, The Penguin Dictionary of Curious and Interesting Numbers, entry 44.
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LINKS
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EXAMPLE
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sigma(20021154)=40894848 > sigma(20021155)=35458560 > ... > sigma(20021159)=20021160.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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