OFFSET
1,2
COMMENTS
Numbers k such that A110566(k) = 1.
Shiu (2016) conjectured that this sequence is infinite. - Amiram Eldar, Feb 02 2021
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Peter Shiu, The denominators of harmonic numbers, arXiv:1607.02863 [math.NT], 2016.
Eric Weisstein's World of Mathematics, Harmonic Number.
MATHEMATICA
Select[Range[250], LCM@@Range[ # ]==Denominator[HarmonicNumber[ # ]]&]
PROG
(PARI) isok(n) = lcm(vector(n, i, i)) == denominator(sum(i=1, n, 1/i)); \\ Michel Marcus, Mar 07 2018
(Python)
from fractions import Fraction
from sympy import lcm
k, l, h, A098464_list = 1, 1, Fraction(1, 1), []
while k < 10**6:
if l == h.denominator:
A098464_list.append(k)
k += 1
l = lcm(l, k)
h += Fraction(1, k) # Chai Wah Wu, Mar 07 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
T. D. Noe, Sep 09 2004
STATUS
approved