OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..100
FORMULA
a(n)/tau(a(n))=2^s with some s, tau()=A000005()
EXAMPLE
a(6)=80: tau(80)=10, quotient=80/10=8=2^3; certain powers of 2 do not appear as quotient, like 64, 1024, 16384.
MATHEMATICA
Do[s=n/DivisorSigma[0, n]; If[IntegerQ[Log[2, s]], Print[{n, s, n/s}]], {n, 1, 1000000000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Dec 04 2002
EXTENSIONS
a(29)-a(34) from Donovan Johnson, Jun 04 2011
STATUS
approved