A168133 Numbers m = sum_(k=1...n) sigma(k) such that sum_(k=1...n) sigma(k) / k is integer for any k.

1, 4, 56, 99, 238, 3276, 26820, 55167, 550514, 3842258, 16222973, 56731455, 118396264, 396379039896, 9772829297132, 15876697439182, 2710103706735457, 4438313663247000, 12136546505785858, 3518811208764622050

Offset

1,2

Comments

Numbers m = A024916(k) such that A024916(k) / k is integer for any k. If a(14) exists it must be bigger than 8*10^9.

Corresponding values of k, and sum_(k=1...n) sigma(k)/k are given in A056550 and A168132. [From Jaroslav Krizek, Nov 21 2009]

Links

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

Example

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

Crossrefs

Sequence in context: A329459 A143650 A143649 * A189864 A360262 A192845

Adjacent sequences: A168130 A168131 A168132 * A168134 A168135 A168136

Keyword

nonn

Author

Jaroslav Krizek, Nov 18 2009, Dec 04 2009

Status

approved