A168132 Numbers m = sum_(k=1...n) sigma(k) / k such that sum_(k=1...n) sigma(k) / k is integer for any k.

1, 2, 7, 9, 14, 52, 149, 213, 673, 1778, 3653, 6831, 9868, 570972, 2835107, 3613594, 47211979, 60418265, 99909506, 1701207282, 4587170542, 10955668024, 29031152874, 114018751785, 813149731047

Offset

1,2

Comments

Numbers m = A024916(k) / k such that A024916(k) / k is integer for any k. If a(14) exist must be bigger than 82000.

Corresponding values of k, and sum_(k=1...n) sigma(k) are given in A056550 and A168133. [From Jaroslav Krizek, Nov 21 2009]

Links

Table of n, a(n) for n=1..25.

Example

Number a(3) = 7 is in sequence because A024916(8) / 8 = 56 / 8 = 7 is integer for k = 8.

Crossrefs

Sequence in context: A341631 A102994 A226824 * A211280 A294863 A085544

Adjacent sequences: A168129 A168130 A168131 * A168133 A168134 A168135

Keyword

nonn

Author

Jaroslav Krizek, Nov 18 2009, Dec 04 2009

Extensions

a(14)-a(25) from Donovan Johnson, Jun 16 2011

Status

approved