

A211200


Indices of records in A207709.


0



1, 11, 113, 7103, 8778881, 2302890927539, 7289913993299309016859, 330513634706872709970497049176749987771, 52698433600606388974675914778280598904460888679269021907794061677149
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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.


LINKS

Table of n, a(n) for n=1..9.


EXAMPLE

A207709(11) = 2 since A207709(113) = 3 is the next record value.


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

Cf. A207709.
Sequence in context: A104096 A239821 A087391 * A048553 A110799 A088089
Adjacent sequences: A211197 A211198 A211199 * A211201 A211202 A211203


KEYWORD

nonn


AUTHOR

Arkadiusz Wesolowski, Apr 04 2012


STATUS

approved



