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A117672 Numbers n such that |cos(n)*cos(n+2)| < (cos(n+1))^2. 1

%I #7 Sep 25 2019 19:18:37

%S 2,3,5,6,8,9,11,12,14,15,17,18,21,24,25,27,28,30,31,33,34,36,37,39,40,

%T 43,46,47,49,50,52,53,55,56,58,59,61,62,65,68,69,71,72,74,75,77,78,80,

%U 81,83,84,87,90,91,93,94,96,97,99,100,102,103,105,106,109,112,113,115

%N Numbers n such that |cos(n)*cos(n+2)| < (cos(n+1))^2.

%C What is the density of the sequence? I am convinced that this sequence has the same density as A026313.

%e |cos(5)*cos(7)| < (cos(6))^2, therefore 5 is in the sequence.

%t Select[Range[120], Abs[Cos[ # ]*Cos[ # + 2]] < Cos[ # + 1]^2 &]

%Y Cf. A026313 [same definition with sin instead of cos].

%K nonn

%O 1,1

%A _Stefan Steinerberger_, Apr 12 2006

%E Offset corrected by _Sean A. Irvine_, Sep 25 2019

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Last modified March 28 03:28 EDT 2024. Contains 371235 sequences. (Running on oeis4.)