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A115890
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Numbers n such that n times sigma(n) 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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(19) > 5*10^10. - Donovan Johnson, Jul 22 2011
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EXAMPLE
| 1664338*sigma(1664338) = 1664338*2688588 = 4474719174744.
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CROSSREFS
| Cf. A084122, A115891, A115892.
Sequence in context: A152005 A140898 A120814 * A101827 A163275 A157073
Adjacent sequences: A115887 A115888 A115889 * A115891 A115892 A115893
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KEYWORD
| nonn,base
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AUTHOR
| Giovanni Resta (g.resta(AT)iit.cnr.it), Feb 06 2006
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EXTENSIONS
| a(13) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Dec 02 2009
a(14)-a(18) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jul 22 2011
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