OFFSET
1,1
COMMENTS
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 01 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 *)
Position[Partition[Sin[Range[200]], 3, 1], _?(#[[1]]>0&&#[[3]]<0&), 1, Heads-> False]// Flatten (* Harvey P. Dale, Sep 04 2022 *)
PROG
(PARI) is(n)=my(x=frac(n/(2*Pi))); 1/2-1/Pi<x && x<1/2 \\ Charles R Greathouse IV, Oct 01 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Oct 01 2016
STATUS
approved