OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..3000
MATHEMATICA
Select[Range[10^6], Plus @@ Times @@@(f = FactorInteger[#]) == 2^Length@f &] (* Amiram Eldar, Dec 01 2019 *)
PROG
(PARI) sopfr(n, s, fac, i) = fac=factor(n); for(i=1, matsize(fac)[1], s=s+fac[i, 1]*fac[i, 2]); return(s);
isok(k) = sopfr(k) == 2^omega(k);
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Sep 12 2001
STATUS
approved