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Numbers k such that cos(k-1) <= 0 and cos(k) > 0.
1

%I #21 Apr 23 2021 01:23:21

%S 5,11,18,24,30,37,43,49,55,62,68,74,81,87,93,99,106,112,118,125,131,

%T 137,143,150,156,162,169,175,181,187,194,200,206,213,219,225,231,238,

%U 244,250,257,263,269,275,282,288,294,301,307,313,319,326,332,338,345

%N Numbers k such that cos(k-1) <= 0 and cos(k) > 0.

%t Select[Range[0, 300], Cos[# - 1] <= 0 && Cos[#] > 0 &] (* _T. D. Noe_, Mar 21 2013 *)

%t SequencePosition[Table[If[Cos[n]>0,1,0],{n,400}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 12 2018 *)

%o (PARI) lista(m) = {for (i=0, m, if ((cos(i-1)<=0) && (cos(i) > 0), print1(i, ", ")););} \\ _Michel Marcus_, Mar 21 2013

%Y Cf. A145005 (except first term). - _Sébastien Dumortier_, Sep 30 2008

%K nonn

%O 1,1

%A _Clark Kimberling_

%E Term 1 removed (at the suggestion of _Michel Marcus_) by _T. D. Noe_, Mar 21 2013