|
%I #15 May 18 2020 12:06:39
%S 2,3,4,8,9,10,14,15,16,20,21,22,23,27,28,29,33,34,35,39,40,41,46,47,
%T 48,52,53,54,58,59,60,64,65,66,67,71,72,73,77,78,79,83,84,85,90,91,92,
%U 96,97,98,102,103,104,108,109,110,111,115,116,117,121,122,123
%N Numbers k such that sin(k) > sin(k+1).
%C The sequences A246293, A246294, A246295, A246296 partition the nonnegative integers.
%C Numbers like 42, 86, 130, 199, 243, 287,.. are in none of these 4 sequences. - _R. J. Mathar_, May 18 2020
%H Clark Kimberling, <a href="/A246293/b246293.txt">Table of n, a(n) for n = 1..4000</a>
%t z = 500; f[x_] := f[x] = Sin[x]; t = Range[0, z];
%t Select[t, f[#] > f[# + 1] &] (* A246293 *)
%t Select[t, f[#] < f[# + 1] > f[# + 2] &] (* A246294 *)
%t Select[t, f[#] < f[# + 1] < f[# + 2] > f[# + 3] &] (* A246295 *)
%t Select[t, f[#] < f[# + 1] < f[# + 2] < f[# + 3] > f[# + 4] &] (* A246296 *)
%t Position[Partition[Sin[Range[130]],2,1],_?(#[[1]]>#[[2]]&),{1},Heads-> False]//Flatten (* _Harvey P. Dale_, Sep 18 2016 *)
%o (PARI) is(n)=sin(n)>sin(n+1) \\ _Charles R Greathouse IV_, Aug 03 2017
%Y Cf. A246294, A246295, A246296, A026309 (complement of A246293).
%K nonn,easy
%O 1,1
%A _Clark Kimberling_, Aug 21 2014
|
