

A168130


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


3




OFFSET

1,2


COMMENTS

Numbers m = A024916(k) such that A024916(k) / A000203(k) is an integer for any k.
Corresponding values of k, sigma (k), and sum_(k=1...n) sigma(k)/sigma(k) are given in A168127, A168129, and A168128. [Jaroslav Krizek, Nov 21 2009]


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

Number a(3) = 690 = A024916(29) is in sequence because A024916(29) / A000203(29) = 690 / 30 = 23 is an integer for k = 29.


PROG

(PARI) m=0; for(k=1, 11413204, s=sigma(k); m=m+s; if(m%s==0, print1(m ", "))) \\ Donovan Johnson, Oct 16 2013


CROSSREFS

Sequence in context: A128875 A199801 A202910 * A037076 A116245 A221198
Adjacent sequences: A168127 A168128 A168129 * A168131 A168132 A168133


KEYWORD

nonn,more


AUTHOR

Jaroslav Krizek, Nov 18 2009, Dec 04 2009


EXTENSIONS

a(8)a(10) from Donovan Johnson, Oct 16 2013


STATUS

approved



