|
%I #10 Oct 15 2013 22:31:45
%S 1,2,8,12,36,80,96,128,288,448,2560,6144,11264,18432,32768,53248,
%T 57344,245760,737280,1114112,2621440,4980736,22020096,23068672,
%U 25165824,66060288,75497472,96468992,436207616,939524096,1258291200,1811939328,2147483648,3774873600
%N Refactorable numbers x, such that quotient x/A000005(x) equals a power of 2.
%H Donovan Johnson, <a href="/A078541/b078541.txt">Table of n, a(n) for n = 1..100</a>
%F a(n)/tau(a(n))=2^s with some s, tau()=A000005()
%e 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.
%t Do[s=n/DivisorSigma[0, n]; If[IntegerQ[Log[2, s]], Print[{n, s, n/s}]], {n, 1, 1000000000}]
%Y Cf. A000005, A033950, A036763, A051278, A051279, A051280.
%K nonn
%O 1,2
%A _Labos Elemer_, Dec 04 2002
%E a(29)-a(34) from _Donovan Johnson_, Jun 04 2011
|
