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 A183164 #6 Mar 30 2012 18:57:12
%S A183164 1,5,4,3,5,7,9,11,13,19,27,41,85,2,61,43,33,29,25,23,21,19,36,17,32,
%T A183164 15,43,28,41,13,76,50,37,24,35,46,57,101,11,97,64,53,42,31,51,71,111,
%U A183164 20,69,49,78,29,67,105,38,47,103,56,74,83,101,128,182,299,9
%N A183164 Least integer k such that k*arctan(n) and k*arctan(n+1) are separated by an integer.
%C A183164 a(n) is the least positive integer for which there is a rational number H with denominator k for which n < tan(H) < n+1.
%t A183164 Table[k=1; While[Floor[k*ArcTan[n+1]]<=k*ArcTan[n], k++];k,{n,100}]
%Y A183164 Cf. A183162, A183163, A183201.
%K A183164 nonn
%O A183164 1,2
%A A183164 _Clark Kimberling_, Dec 27 2010