OFFSET
1,1
COMMENTS
Numbers like 20, 64, 108, 152, 177, 221, 265, 309, ... are in none of these 4 sequences. - R. J. Mathar, May 18 2020
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..987
MATHEMATICA
z = 500; f[x_] := f[x] = Sin[x]; t = Range[0, z];
Select[t, f[#] < f[# + 1] &] (* A026309 *)
Select[t, f[#] > f[# + 1] < f[# + 2] &] (* A246297 *)
Select[t, f[#] > f[# + 1] > f[# + 2] < f[# + 3] &] (* A246298 *)
Select[t, f[#] > f[# + 1] > f[# + 2] > f[# + 3] < f[# + 4] &] (* A246299 *)
Position[Partition[Table[Sin[n], {n, 400}], 5, 1], _?(#[[1]]>#[[2]]>#[[3]]>#[[4]]<#[[5]]&), 1, Heads->False]//Flatten (* Harvey P. Dale, May 13 2023 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Aug 21 2014
EXTENSIONS
Corrected signs in NAME. - R. J. Mathar, May 18 2020
STATUS
approved