A246406 Nonnegative integers k satisfying sec(k) > sec(k+1) > sec(k+2) < sec(k+3).

11, 55, 99, 143, 210, 254, 298, 342, 388, 432, 476, 520, 543, 587, 631, 675, 721, 765, 809, 853, 920, 964, 1008, 1052, 1098, 1142, 1186, 1230, 1253, 1297, 1341, 1385, 1431, 1475, 1519, 1563, 1630, 1674, 1718, 1762, 1808, 1852, 1896, 1940, 1963, 2007, 2051

Offset

1,1

Comments

A246404, A246405, and A246406 partition the nonnegative integers.

Links

Clark Kimberling, Table of n, a(n) for n = 1..2000

Mathematica

z = 500; f[x_] := f[x] = Sec[x];
Select[Range[0, z], f[#] < f[# + 1] &]  (* A246404 *)
Select[Range[0, z], f[#] > f[# + 1] < f[# + 2] &]  (* A246405 *)
Select[Range[0, z], f[#] > f[# + 1] > f[# + 2] < f[# + 3] &]  (* A246406 *)
Position[Partition[Sec[Range[2100]], 4, 1], _?(#[[1]]>#[[2]]>#[[3]]< #[[4]]&), 1, Heads->False]//Flatten (* Harvey P. Dale, Mar 10 2019 *)

Crossrefs

Cf. A246404, A246405.

Sequence in context: A200172 A348025 A050900 * A255415 A153449 A047649

Adjacent sequences: A246403 A246404 A246405 * A246407 A246408 A246409

Keyword

nonn,easy

Author

Clark Kimberling, Aug 25 2014

Status

approved