login
A246304
Numbers k such that cos(k) > cos(k+1) < cos(k+2).
4
2, 8, 15, 21, 27, 34, 40, 46, 52, 59, 65, 71, 78, 84, 90, 96, 103, 109, 115, 122, 128, 134, 140, 147, 153, 159, 166, 172, 178, 184, 191, 197, 203, 209, 216, 222, 228, 235, 241, 247, 253, 260, 266, 272, 279, 285, 291, 297, 304, 310, 316, 323, 329, 335, 341
OFFSET
1,1
COMMENTS
The sequences A246303, A246304, A246305, A246306 partition the nonnegative integers.
LINKS
MATHEMATICA
z = 500; f[x_] := f[x] = Cos[x]; t = Range[0, z];
Select[t, f[#] < f[# + 1] &] (* A246303 *)
Select[t, f[#] > f[# + 1] < f[# + 2] &] (* A246304 *)
Select[t, f[#] > f[# + 1] > f[# + 2] < f[# + 3] &] (* A246305 *)
Select[t, f[#] > f[# + 1] > f[# + 2] > f[# + 3] < f[# + 4] &] (* A246306 *)
Flatten[Position[Partition[Cos[Range[400]], 3, 1], _?(#[[1]]>#[[2]] && #[[2]]< #[[3]]&), {1}, Heads->False]] (* Harvey P. Dale, Apr 23 2015 *)
CROSSREFS
Cf. A026303, A246305, A246306, A026311 (complement of A246303).
Sequence in context: A031272 A277139 A213082 * A063286 A133230 A318242
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Aug 22 2014
STATUS
approved