A327423 Positive integers k such that tan(k) < 0 (or equivalently, cot(k) < 0).

2, 3, 5, 6, 8, 9, 11, 12, 15, 18, 21, 24, 25, 27, 28, 30, 31, 33, 34, 37, 40, 43, 46, 47, 49, 50, 52, 53, 55, 56, 59, 62, 65, 68, 69, 71, 72, 74, 75, 77, 78, 81, 84, 87, 90, 91, 93, 94, 96, 97, 99, 100, 103, 106, 109, 112, 113, 115, 116, 118, 119, 121, 122, 125, 128

Offset: 1

Author

Jianing Song, Nov 29 2019

Keywords

• nonn

Comments

Complement of A327422.

Numbers k such that 1/2 < {k/Pi} < 1, 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 A070751.

Crossrefs

Cf. 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), A327422 (tan(k) > 0 or cot(k) > 0), this sequence (tan(k) < 0 or cot(k) < 0).

Programs

Mathematica

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

PARI

A327423_up_to_n(n) = my(v=vector(n,k,k)); select(k->tan(k)<0,v)