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A026311
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n-th nonnegative integer k satisfying cos(k) > cos(k+1).
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8
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0, 1, 2, 6, 7, 8, 13, 14, 15, 19, 20, 21, 25, 26, 27, 31, 32, 33, 34, 38, 39, 40, 44, 45, 46, 50, 51, 52, 57, 58, 59, 63, 64, 65, 69, 70, 71, 75, 76, 77, 78, 82, 83, 84, 88, 89, 90, 94, 95, 96, 101, 102, 103, 107, 108, 109, 113, 114, 115
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OFFSET
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1,3
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COMMENTS
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LINKS
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MATHEMATICA
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z = 520; f[x_] := f[x] = Cos[x]; t = Range[0, z];
Select[t, f[#] > f[# + 1] &] (* A026311 *)
Select[t, f[#] < f[# + 1] > f[# + 2] &] (* A246300 *)
Select[t, f[#] < f[# + 1] < f[# + 2] > f[# + 3] &] (* A246301 *)
Select[t, f[#] < f[# + 1] < f[# + 2] < f[# + 3] > f[# + 4] &] (* A246302 *)
Join[{0}, Position[Partition[Cos[Range[120]], 2, 1], _?(#[[1]]>#[[2]]&), 1, Heads -> False]//Flatten] (* Harvey P. Dale, Aug 09 2021 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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