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A179664 Products of the 7th power of a prime and a distinct prime (p^7*q). 12


%S 384,640,896,1408,1664,2176,2432,2944,3712,3968,4374,4736,5248,5504,

%T 6016,6784,7552,7808,8576,9088,9344,10112,10624,10935,11392,12416,

%U 12928,13184,13696,13952,14464,15309,16256,16768,17536,17792,19072,19328

%N Products of the 7th power of a prime and a distinct prime (p^7*q).

%H T. D. Noe, <a href="/A179664/b179664.txt">Table of n, a(n) for n = 1..1000</a>

%H Will Nicholes, <a href="http://willnicholes.com/math/primesiglist.htm">Prime Signatures</a>

%H <a href="/index/Pri#prime_signature">Index to sequences related to prime signature</a>

%F Solutions of the equation tau(n^9)=40*tau(n). - _Paolo P. Lava_, Mar 18 2013

%p A179664:=proc(q) local n;

%p for n from 1 to q do if tau(n^9)=40*tau(n) then print(n); fi; od; end:

%p A179664(10^10); # _Paolo P. Lava_, Mar 18 2013

%t f[n_]:=Sort[Last/@FactorInteger[n]]=={1,7};Select[Table[n,{n,8!}],f[ # ]&]

%o (PARI) list(lim)=my(v=List(),t);forprime(p=2,(lim\2)^(1/7),t=p^7;forprime(q=2,lim\t,if(p==q,next);listput(v,t*q)));vecsort(Vec(v)) \\ _Charles R Greathouse IV_, Jul 20 2011

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jul 23 2010

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Last modified February 19 11:10 EST 2019. Contains 320310 sequences. (Running on oeis4.)