[seqfan] Number of solutions of sigma(x) = n.

Allan Wechsler acwacw at gmail.com
Tue May 13 22:04:21 CEST 2014


If I have done this right, the first few entries are 1, 0, 1, 1, 0, 2, 1,
1, 0, 0. For example, a(6) = 2 because sigma(5) = sigma(6) = 6, and a(24) =
3 because sigma(14) = sigma(15) = sigma(23) = 24.

If my paper calculations were right for the first few entries, I am really
surprised to find this missing from OEIS, and am inclined to nominate it
for sequence A250000. It has many links with existing sequences relating to
sums of divisors.


More information about the SeqFan mailing list