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A115890
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Numbers k such that k*sigma(k) is a palindrome.
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5
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1, 2, 141, 517, 1089, 1621, 1651, 2359, 17529, 20086, 124282, 1664338, 72452549, 1503846167, 14457164981, 17107594211, 17458514913, 24556027479
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OFFSET
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1,2
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COMMENTS
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a(19) > 5*10^10. - Donovan Johnson, Jul 22 2011
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LINKS
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Table of n, a(n) for n=1..18.
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EXAMPLE
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1664338*sigma(1664338) = 1664338*2688588 = 4474719174744.
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CROSSREFS
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Cf. A084122, A115891, A115892.
Sequence in context: A120814 A221601 A334013 * A356747 A215187 A101827
Adjacent sequences: A115887 A115888 A115889 * A115891 A115892 A115893
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KEYWORD
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nonn,base,more
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AUTHOR
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Giovanni Resta, Feb 06 2006
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EXTENSIONS
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a(13) from Donovan Johnson, Dec 02 2009
a(14)-a(18) from Donovan Johnson, Jul 22 2011
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STATUS
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approved
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