A246393 - OEIS

A246393

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

1, 7, 14, 20, 26, 32, 39, 45, 51, 58, 64, 70, 76, 83, 89, 95, 102, 108, 114, 120, 127, 133, 139, 146, 152, 158, 164, 171, 177, 183, 190, 196, 202, 208, 215, 221, 227, 234, 240, 246, 252, 259, 265, 271, 278, 284, 290, 296, 303, 309, 315, 322, 328, 334, 340

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OFFSET

0,2

COMMENTS

A246393 and A246394 partition A062389 (the nonhomogeneous Beatty sequence {floor(-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, A246394, A246046, A246395, A246396, A246388.