OFFSET
1,2
COMMENTS
Least k such that (H(k) + exp(H(k))*log(H(k)))/sigma(k) >= n, where H(k) is the harmonic number sum_{i=1..k} 1/i.
a(10) has 119 digits and is too large to include.
Conjecture: the sequence contains only noncomposite numbers.
MATHEMATICA
lst = {}; h = k = n = 0; Do[While[n <= max, k++; h = h + 1/k; n = (h + Exp@h*Log@h)/DivisorSigma[1, k]]; AppendTo[lst, k], {max, 2, 4}]; Prepend[lst, 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Arkadiusz Wesolowski, Apr 04 2012
STATUS
approved