A327422 - OEIS

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A327422

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

1, 4, 7, 10, 13, 14, 16, 17, 19, 20, 22, 23, 26, 29, 32, 35, 36, 38, 39, 41, 42, 44, 45, 48, 51, 54, 57, 58, 60, 61, 63, 64, 66, 67, 70, 73, 76, 79, 80, 82, 83, 85, 86, 88, 89, 92, 95, 98, 101, 102, 104, 105, 107, 108, 110, 111, 114, 117, 120, 123, 124, 126, 127, 129

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OFFSET

1,2

COMMENTS

Complement of A327423.

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

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

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

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..10000

MATHEMATICA

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

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

Select[Range[130], Tan[#]>0&] (* Harvey P. Dale, Aug 26 2021 *)

PROG

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

(Magma) [n : n in[1..300]|Tan(n) gt 0]; // K. D. Bajpai, Dec 15 2019

CROSSREFS

Cf. A327423, A330035.

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).

Sequence in context: A184850 A331207 A090384 * A260165 A055054 A196415

Adjacent sequences: A327419 A327420 A327421 * A327423 A327424 A327425

KEYWORD

nonn

AUTHOR

Jianing Song, Nov 29 2019

STATUS

approved