A115890 Numbers k such that k*sigma(k) is a palindrome.

1, 2, 141, 517, 1089, 1621, 1651, 2359, 17529, 20086, 124282, 1664338, 72452549, 1503846167, 14457164981, 17107594211, 17458514913, 24556027479

Offset

1,2

Comments

a(19) > 5*10^10. - Donovan Johnson, Jul 22 2011

Links

Table of n, a(n) for n=1..18.

Example

1664338*sigma(1664338) = 1664338*2688588 = 4474719174744.

Crossrefs

Cf. A084122, A115891, A115892.

Sequence in context: A120814 A221601 A334013 * A356747 A215187 A101827

Adjacent sequences: A115887 A115888 A115889 * A115891 A115892 A115893

Keyword

nonn,base,more

Author

Giovanni Resta, Feb 06 2006

Extensions

a(13) from Donovan Johnson, Dec 02 2009

a(14)-a(18) from Donovan Johnson, Jul 22 2011

Status

approved