%I #26 Sep 08 2022 08:46:24

%S 1,4,7,10,13,14,16,17,19,20,22,23,26,29,32,35,36,38,39,41,42,44,45,48,

%T 51,54,57,58,60,61,63,64,66,67,70,73,76,79,80,82,83,85,86,88,89,92,95,

%U 98,101,102,104,105,107,108,110,111,114,117,120,123,124,126,127,129

%N Positive integers k such that tan(k) > 0 (or equivalently, cot(k) > 0).

%C Complement of A327423.

%C Numbers k such that 0 < {k/Pi} < 1/2, where {} is the fractional part.

%C Numbers k such that A330035(k) = +1.

%C Also positive integers k such that sin(2k) > 0, i.e., k such that 2k is in A070752.

%H K. D. Bajpai, <a href="/A327422/b327422.txt">Table of n, a(n) for n = 1..10000</a>

%t upto[n_] := Select[Range[n], Tan[#] > 0 &]

%t A327422={}; Do[ If[Tan[n] > 0, AppendTo[A327422, n]],{n, 200}]; A327422 (* _K. D. Bajpai_, Dec 15 2019 *)

%t Select[Range[130],Tan[#]>0&] (* _Harvey P. Dale_, Aug 26 2021 *)

%o (PARI) A327422_up_to_n(n) = my(v=vector(n,k,k)); select(k->tan(k)>0,v)

%o (Magma) [n : n in[1..300]|Tan(n) gt 0]; // _K. D. Bajpai_, Dec 15 2019

%Y Cf. A327423, A330035.

%Y Cf. A070752 (sin(k) > 0 or csc(k) > 0), A070751 (sin(k) < 0 or csc(k) < 0), A131503 (cos(k) > 0 or sec(k) > 0), this sequence (tan(k) > 0 or cot(k) > 0), A327423 (tan(k) < 0 or cot(k) < 0).

%K nonn

%O 1,2

%A _Jianing Song_, Nov 29 2019