This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A327136 #14 Jun 22 2021 01:06:21 %S A327136 1,4,8,11,14,17,20,23,26,30,33,36,39,42,45,48,52,55,58,61,64,67,70,74, %T A327136 77,80,83,86,89,92,96,99,102,105,108,111,114,118,121,124,127,130,133, %U A327136 136,140,143,146,149,152,155,158,162,165,168,171,174,177,180,184 %N A327136 Numbers k such that sin(2k) > sin(2k+2) < sin(2k+4). %C A327136 The sequences A026317, A327136, A327137 partition the nonnegative integers. %C A327136 Conjecture: 1.285 < n*Pi - a(n) < 1.286 for n >= 1. %H A327136 Clark Kimberling, <a href="/A327136/b327136.txt">Table of n, a(n) for n = 1..10000</a> %e A327136 (sin 2, sin 4, ...) = (0.9, -0.7, -0.2, 0.9, -0.5, ...) approximately, so that the differences, in sign, are - + + - + + - - + - - + ..., with "+" in places 2,3,5,6,... (A026317), "- +" starting in places 1,4,8,11,... (A327136), and "- - +" starting in places 7,10,13,16,... (A327137). %t A327136 z = 500; f[x_] := f[x] = Sin[2 x]; t = Range[1, z]; %t A327136 Select[t, f[#] < f[# + 1] &] (* A026317 *) %t A327136 Select[t, f[#] > f[# + 1] < f[# + 2] &] (* A327136 *) %t A327136 Select[t, f[#] > f[# + 1] > f[# + 2] < f[# + 3] &] (* A327137 *) %Y A327136 Cf. A026309, A246303, A026317. %K A327136 nonn,easy %O A327136 1,2 %A A327136 _Clark Kimberling_, Aug 23 2019