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A134716
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a(n) = least number m such that sigma(m)/m > n, where sigma(m) = sum of divisors of m.
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1
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1, 2, 12, 180, 27720, 122522400, 130429015516800, 1970992304700453905270400, 1897544233056092162003806758651798777216000, 4368924363354820808981210203132513655327781713900627249499856876120704000
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OFFSET
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0,2
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LINKS
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Table of n, a(n) for n=0..9.
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EXAMPLE
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Values written as products of primorials:
n a(n)
0 1
1 2
2 2*3#
3 3#*5# (= 180)
4 2*3#*11#
5 8*5#*17#
6 16*3#*7#*29#
7 8*3#*3#*7#*53#
8 32*3#*3#*5#*11#*89#
9 32*3#*3#*7#*17#*157#
10 16*3#*3#*5#*7#*23#*271#
11 16*3#*3#*5#*7#*29#*487#
12 16*3#*3#*5#*7#*13#*31#*857#
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CROSSREFS
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Cf. A023199 (least k with sigma(k) >= nk)
Sequence in context: A125861 A156516 A067962 * A006023 A039748 A007764
Adjacent sequences: A134713 A134714 A134715 * A134717 A134718 A134719
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KEYWORD
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nonn
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AUTHOR
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Pierre CAMI, Jan 27 2008, corrected Feb 26 2008 with the help of Emeric Deutsch
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EXTENSIONS
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More terms can be obtained by expanding the expressions in the example lines. - N. J. A. Sloane, Feb 26 2008
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STATUS
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approved
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