OFFSET
1,2
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..9268
EXAMPLE
6 is a term because floor(Sum_{d|6} 1/sigma(d)) = floor(1/1 + 1/3 + 1/4 + 1/12) = floor(5/3) = 1.
MATHEMATICA
Select[Range@ 73, Floor[Sum[1/DivisorSigma[1, d], {d, Divisors@ #}]] == 1 &] (* Michael De Vlieger, Dec 31 2015 *)
PROG
(Magma) [n: n in [1..1000] | Floor(&+[1/SumOfDivisors(d): d in Divisors(n)]) eq 1]
(PARI) isok(n) = floor(sumdiv(n, d, 1/sigma(d))) == 1; \\ Michel Marcus, Dec 27 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 25 2015
STATUS
approved