Voozh

A246394

Nonnegative integers k satisfying cos(k) <= 0 and cos(k+1) >= 0.

4, 10, 17, 23, 29, 36, 42, 48, 54, 61, 67, 73, 80, 86, 92, 98, 105, 111, 117, 124, 130, 136, 142, 149, 155, 161, 168, 174, 180, 186, 193, 199, 205, 212, 218, 224, 230, 237, 243, 249, 256, 262, 268, 274, 281, 287, 293, 300, 306, 312, 318, 325, 331, 337, 344

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

COMMENTS

A246393 and A246394 partition A062389 (the nonhomogeneous Beatty sequence {floor((n-1/2)*Pi)}). Likewise, A246046, the complement of A062389, is partitioned by A246395 and A246396. (See the Mathematica program.)

LINKS

Clark Kimberling, Table of n, a(n) for n = 0..1000

MATHEMATICA

z = 400; f[x_] := Cos[x]

Select[Range[0, z], f[#]*f[# + 1] <= 0 &] (* A062389 *)

Select[Range[0, z], f[#] >= 0 && f[# + 1] <= 0 &] (* A246393 *)

Select[Range[0, z], f[#] <= 0 && f[# + 1] >= 0 &] (* A246394 *)

Select[Range[0, z], f[#]*f[# + 1] > 0 &] (* A246046 *)

Select[Range[0, z], f[#] >= 0 && f[# + 1] >= 0 &] (* A246395 *)

Select[Range[0, z], f[#] <= 0 && f[# + 1] <= 0 &] (* A246396 *)

CROSSREFS

Cf. A062389, A246393, A246046, A246395, A246396.