OFFSET
1,2
COMMENTS
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..47
MATHEMATICA
a245787[n_Integer] := Select[Range[n], Divisible[#^2, DivisorSigma[0, #]*DivisorSigma[1, #]]&] (* Michael De Vlieger, Aug 09 2014 *)
PROG
(Magma) [n: n in [1..1000000] | Denominator(n^2 / ((#[d: d in Divisors(n)])* SumOfDivisors(n))) eq 1]
(PARI)
for(n=1, 10^8, if(n^2%(numdiv(n)*sigma(n))==0, print1(n, ", "))) \\ Derek Orr, Aug 08 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 08 2014
EXTENSIONS
a(7)-a(10) from Derek Orr, Aug 08 2014
a(11)-a(26) from Jens Kruse Andersen, Aug 13 2014
STATUS
approved