OFFSET
1,2
COMMENTS
If k is an odd term > 1 then 2*k is also in the sequence.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
EXAMPLE
65 is a term since A050999(65) = 4420 = 65 * 68 is divisible by 65.
MATHEMATICA
f[p_, e_] := If[p == 2, 1, (p^(2*e + 2) - 1)/(p^2 - 1)]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[10^5], Divisible[s[#], #] &]
PROG
(PARI) f(n) = sumdiv(n, d, if(d%2==1, d^2, 0 ) ); \\ A050999
isok(k) = !(f(k) % k); \\ Michel Marcus, Jul 07 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jul 06 2022
STATUS
approved