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A246390 Nonnegative integers k satisfying sin(k) <= 0 and sin(k+1) <= 0.

%I A246390 #7 Apr 02 2023 13:50:17
%S A246390 4,5,10,11,16,17,22,23,24,29,30,35,36,41,42,48,49,54,55,60,61,66,67,
%T A246390 68,73,74,79,80,85,86,92,93,98,99,104,105,110,111,112,117,118,123,124,
%U A246390 129,130,136,137,142,143,148,149,154,155,156,161,162,167,168,173
%N A246390 Nonnegative integers k satisfying sin(k) <= 0 and sin(k+1) <= 0.
%C A246390 A246388 and A038130 (Beatty sequence for 2*Pi) partition A022844 (Beatty sequence for Pi). Likewise, A054386, the complement of A022844, is partitioned by A246389 and A246390. (See the Mathematica program.)
%H A246390 Clark Kimberling, <a href="/A246390/b246390.txt">Table of n, a(n) for n = 0..1000</a>
%t A246390 z = 400; f[x_] := Sin[x]
%t A246390 Select[Range[0, z], f[#]*f[# + 1] <= 0 &] (* A022844 *)
%t A246390 Select[Range[0, z], f[#] >= 0 && f[# + 1] <= 0 &]  (* A246388 *)
%t A246390 Select[Range[0, z], f[#] <= 0 && f[# + 1] >= 0 &] (* A038130 *)
%t A246390 Select[Range[0, z], f[#]*f[# + 1] > 0 &] (* A054386 *)
%t A246390 Select[Range[0, z], f[#] >= 0 && f[# + 1] >= 0 &]  (* A246389 *)
%t A246390 Select[Range[0, z], f[#] <= 0 && f[# + 1] <= 0 &] (* A246390 *)
%t A246390 SequencePosition[Table[If[Sin[n]<=0,1,0],{n,200}],{1,1}][[;;,1]] (* _Harvey P. Dale_, Apr 02 2023 *)
%Y A246390 Cf. A022844, A038130, A054386, A246388, A246389.
%K A246390 nonn,easy
%O A246390 0,1
%A A246390 _Clark Kimberling_, Aug 24 2014