A004082 Numbers k such that sin(k-1) <= 0 and sin(k) > 0.

1, 7, 13, 19, 26, 32, 38, 44, 51, 57, 63, 70, 76, 82, 88, 95, 101, 107, 114, 120, 126, 132, 139, 145, 151, 158, 164, 170, 176, 183, 189, 195, 202, 208, 214, 220, 227, 233, 239, 246, 252, 258, 264, 271, 277, 283, 290, 296

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

Apart from the first term this is also the sequence ceiling(circumference of a circle of radius n) = ceiling(2*Pi*n), n >= 1. - Mohammad K. Azarian, Feb 29 2008, Aug 01 2009

Bisection of A004084. - Michel Marcus, Mar 21 2013

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A004084, A066643.

For floor(2*Pi*n) see A038130.

See A277690 for another version.

Programs

Mathematica

Join[{1},Transpose[SequencePosition[Table[If[Sin[n]<=0,1,0],{n,300}],{1,0}]][[2]]] (* The program uses the SequencePosition function from Mathematica version 10 *) (* Harvey P. Dale, Apr 12 2016 *)

PARI

lista(m) = {for (i=1, m, if ((sin(i-1)<=0) && (sin(i) > 0), print1(i, ", ")););} \\ Michel Marcus, Mar 21 2013

Formula

a(n) = A038130(n-1) + 1.