A277095 Numbers k such that sin(k) < 0 and sin(k+2) > 0.

5, 6, 11, 12, 17, 18, 24, 25, 30, 31, 36, 37, 42, 43, 49, 50, 55, 56, 61, 62, 68, 69, 74, 75, 80, 81, 86, 87, 93, 94, 99, 100, 105, 106, 112, 113, 118, 119, 124, 125, 130, 131, 137, 138, 143, 144, 149, 150, 156, 157, 162, 163, 168, 169, 174, 175, 181, 182

Offset

1,1

Comments

Guide to related sequences (a four-way splitting of the natural numbers):

A277093: sin(k) > 0 and sin(k+2) > 0

A277094: sin(k) > 0 and sin(k+2) < 0

A277095: sin(k) < 0 and sin(k+2) > 0

A277096: sin(k) < 0 and sin(k+2) < 0

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ Pi*n by the equidistribution theorem. - Charles R Greathouse IV, Oct 09 2016

Mathematica

z = 400; f[x_] := Sin[x];
Select[Range[z], f[#] > 0 && f[# + 2] > 0 &] (* A277093 *)
Select[Range[z], f[#] > 0 && f[# + 2] < 0 &] (* A277094 *)
Select[Range[z], f[#] < 0 && f[# + 2] > 0 &] (* A277095 *)
Select[Range[z], f[#] < 0 && f[# + 2] < 0 &] (* A277096 *)

Prog

(PARI) is(n)=frac(n/2/Pi) > 1-1/Pi \\ Charles R Greathouse IV, Oct 09 2016

Crossrefs

Cf. A277093, A277094, A277096.

Sequence in context: A047264 A343405 A369273 * A332482 A190895 A129286

Adjacent sequences: A277092 A277093 A277094 * A277096 A277097 A277098

Keyword

nonn,easy

Author

Clark Kimberling, Oct 01 2016

Status

approved