This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A163581 #12 Aug 07 2013 03:25:09 %S A163581 0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,0,1,0,0,1,0,0,1,0,0, %T A163581 1,0,0,1,0,0,1,0,0,1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0, %U A163581 0,1,0,0,1,0,0,1,0,0,1,0,0 %N A163581 Number of zeros of sin(x) in integer intervals starting with (0,1). %F A163581 a(n) = 1 if n < m*pi < (n+1) for any positive integer m; a(n) = 0 otherwise. %F A163581 For n>0, a(A022844(n)) = 1. - _Michel Marcus_, Aug 07 2013 %e A163581 For n = 0, 1 and 2, sin(x) has no zeros in the intervals (0,1), (1,2) and (2,3), respectively, so a(0), a(1) and a(2) are all zero. For n = 3, sin(x) has a zero in the interval (3,4) at x = pi, so a(3) = 1. %Y A163581 Cf. A163584. %K A163581 nonn %O A163581 0,1 %A A163581 _A. Timothy Royappa_, Jul 31 2009