OFFSET
1,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..93
MATHEMATICA
Select[Range[3000], PrimeQ[Numerator[Sum[(i-1)/i, {i, #}]]]&] (* Harvey P. Dale, Jul 13 2011 *)
Position[Accumulate[Table[(k-1)/k, {k, 3000}]], _?(PrimeQ[Numerator[#]]&)]// Flatten (* Harvey P. Dale, Jun 06 2021 *)
PROG
(PARI) ss(n)=sum(i=1, n, (i-1)/i); for (i=1, 1200, if(isprime(numerator(ss(i))), print1(i, ".")))
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 07 2004
EXTENSIONS
a(39)-a(46) from Harvey P. Dale, Jul 13 2011
a(47) and beyond from Michael S. Branicky, Aug 26 2024
STATUS
approved