OFFSET
1,2
COMMENTS
k+1 must be a prime, but converse is not true.
EXAMPLE
The sum of the first 4 harmonic numbers is 77/12 and 12 is lcm(1,2,3,4).
MATHEMATICA
big=Table[LCM @@Range[n]/Denominator[ -n+(1+n) HarmonicNumber[n]], {n, 2048}]; Position[big, 1]//Flatten
PROG
(PARI) h(n) = sum(j=1, n, 1/j);
isok(n) = lcm(vector(n, k, k)) == denominator(sum(k=1, n, h(k))); \\ Michel Marcus, Mar 15 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Wouter Meeussen, Apr 13 2003
EXTENSIONS
More terms from Wouter Meeussen, Feb 21 2004
STATUS
approved