OFFSET
0,2
EXAMPLE
PROG
(PARI) a240923(n) = my(ab = sigma(n)/n); numerator(ab) - sigma(denominator(ab));
a(n) = my(k = 1); while(a240923(k) != n, k++); k;
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Aug 06 2014
STATUS
approved