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A160685 Numbers k >= 1 such that A000005(A000045(k))/A000005(k) is an integer.

%I A160685 #12 May 17 2023 13:02:02
%S A160685 1,3,5,6,7,8,10,11,13,14,15,17,19,21,22,23,24,25,26,27,29,30,31,33,34,
%T A160685 35,37,38,39,40,41,42,43,46,47,50,51,53,54,55,56,57,58,59,60,61,62,65,
%U A160685 66,67,69,70,71,72,73,74,75,77,78,79,82,83,84,85,86,87,88,89,91,93,94
%N A160685 Numbers k >= 1 such that A000005(A000045(k))/A000005(k) is an integer.
%C A160685 A080651 is a subsequence. - _R. J. Mathar_, May 25 2009
%H A160685 Robert Israel, <a href="/A160685/b160685.txt">Table of n, a(n) for n = 1..1073</a>
%F A160685 {n: A000005(n) | A063375(n)}. - _R. J. Mathar_, May 25 2009
%p A160685 A000045 := proc(n) combinat[fibonacci](n) ; end: A000005 := proc(n) numtheory[tau](n) ; end: A063375 := proc(n) A000005(A000045(n)) ; end: for n from 1 to 130 do if A063375(n) mod A000005(n) = 0 then printf("%d,",n) ; fi; od: # _R. J. Mathar_, May 25 2009
%t A160685 okQ[n_] := With[{tau = DivisorSigma[0, #]&},
%t A160685   IntegerQ[tau[Fibonacci[n]]/tau[n]]];
%t A160685 Select[Range[100], okQ] (* _Jean-François Alcover_, May 17 2023 *)
%Y A160685 Cf. A000045, A000005.
%K A160685 easy,nonn
%O A160685 1,2
%A A160685 _Ctibor O. Zizka_, May 23 2009
%E A160685 2, 12 removed and sequence extended by _R. J. Mathar_, May 25 2009