“…The problem is so intractable that, up until recently, there had been no viable guess for the exact value of
. The approach of using correlations of divisor sums leads to conjectures for
and
[
8, 9], and the process has recently been examined in close detail and made more precise by Ng [24], Hamieh and Ng [
20], and Ng, Shen, and Wong [25]. This approach seems to fail, however, to give a reasonable guess for
when
[
9].…”