A243810 - OEIS

A243810

Odd squares which are the sum of the divisors of some n.

1, 121, 961, 116281, 294849, 423801, 2989441, 7958041, 26904969, 35676729, 51279921, 71622369, 361722361, 962922961, 1891467081, 1902442689, 3255501249, 4364319969, 4755619521, 5215583961, 6431879601, 6561486009, 6835486329, 7496615889, 8666306649, 9712693809

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Odd terms of A038688, where most of the terms are even.

The corresponding values in A228061 are: 1, 11, 31, 341, 543, 651, 1729, 2821, ...

Among the known terms, the only prime powers are 121 and 961.

Next term is greater than 10^8.

LINKS

Hiroaki Yamanouchi, Table of n, a(n) for n = 1..183

EXAMPLE

121 being an odd square and satisfying sigma(81) = 121, 121 is in the sequence.