A246300 Numbers k such that cos(k) < cos(k+1) > cos(k+2).

5, 12, 18, 24, 30, 37, 43, 49, 56, 62, 68, 74, 81, 87, 93, 100, 106, 112, 118, 125, 131, 137, 144, 150, 156, 162, 169, 175, 181, 187, 194, 200, 206, 213, 219, 225, 231, 238, 244, 250, 257, 263, 269, 275, 282, 288, 294, 301, 307, 313, 319, 326, 332, 338, 345

Offset: 1

Author

Clark Kimberling, Aug 22 2014

Keywords

• nonn
• easy

Comments

The sequences A026311, A246300, A246301, A246302 partition the nonnegative integers.

Links

• Clark Kimberling, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A246294, A026311, A246301, A246302.

Programs

Mathematica

z = 520; f[x_] := f[x] = Cos[x]; t = Range[0, z];
Select[t, f[#] > f[# + 1] &]  (* A026311 *)
Select[t, f[#] < f[# + 1] > f[# + 2] &]  (* A246300 *)
Select[t, f[#] < f[# + 1] < f[# + 2] > f[# + 3] &]  (* A246301 *)
Select[t, f[#] < f[# + 1] < f[# + 2] < f[# + 3] > f[# + 4] &] (* A246302 *)
Flatten[Position[Partition[Cos[Range[350]],3,1],?(#[[1]]<#[[2]]>#[[3]]&),1,Heads->False]] (* _Harvey P. Dale, Jan 20 2025 *)