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A073752 Greatest common divisor of n/spf(n) and n/gpf(n) where spf(n) is the smallest and gpf(n) is the greatest prime factor of n (see A020639, A006530). 3

%I #8 Jun 17 2012 18:23:51

%S 1,1,1,2,1,1,1,4,3,1,1,2,1,1,1,8,1,3,1,2,1,1,1,4,5,1,9,2,1,3,1,16,1,1,

%T 1,6,1,1,1,4,1,3,1,2,3,1,1,8,7,5,1,2,1,9,1,4,1,1,1,6,1,1,3,32,1,3,1,2,

%U 1,5,1,12,1,1,5,2,1,3,1,8,27,1,1,6,1,1,1,4,1,9,1,2,1,1,1,16,1,7,3,10,1

%N Greatest common divisor of n/spf(n) and n/gpf(n) where spf(n) is the smallest and gpf(n) is the greatest prime factor of n (see A020639, A006530).

%C a(n) = if n=p^k (p prime, k>0) then p^(k-1) else n/(spf(n)*gpf(n)).

%H Harvey P. Dale, <a href="/A073752/b073752.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = GCD(A032742(n), A052126(n)).

%t gc[n_]:=Module[{fi=Transpose[FactorInteger[n]][[1]]},GCD[n/First[fi], n/Last[ fi]]]; Array[gc,110] (* _Harvey P. Dale_, Jun 17 2012 *)

%Y Cf. A000961, A066048.

%Y A073753(n) = a(a(n)).

%K nonn

%O 1,4

%A _Reinhard Zumkeller_, Aug 07 2002

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Last modified June 5 08:53 EDT 2024. Contains 373104 sequences. (Running on oeis4.)