OFFSET
1,1
COMMENTS
Also in the sequence is 21623407345626345971712000.
a(13) > 5*10^12. - Giovanni Resta, Mar 14 2019
EXAMPLE
36720 is in the sequence since its sum of tri-unitary divisors is A324706(36720) = 73440 = 2 * 36720.
MATHEMATICA
f[p_, e_] := If[e == 3, (p^4-1)/(p-1), If[e==6, (p^8-1)/(p^2-1), p^e+1]]; tsigma[1]=1; tsigma[n_]:= Times @@ f @@@ FactorInteger[n]; Select[Range[50000], tsigma[#]==2# &]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Mar 11 2019
EXTENSIONS
a(11)-a(12) from Giovanni Resta, Mar 14 2019
STATUS
approved