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 A135039 #18 Oct 15 2017 21:11:25 %S A135039 0,4,13,29,51,79,114,154,202,255,315,381,453,531,616,707,805,908,1018, %T A135039 1135,1257,1386,1521,1662,1810,1964,2124,2291,2464,2643,2828,3020, %U A135039 3217,3422,3632,3849,4072,4301,4537,4779,5027,5282,5542,5809,6083,6362,6648 %N A135039 Ceiling(Pi*n^2). %C A135039 Old name was "a(n)=ceiling[area of a circle of radius n]". %H A135039 Vincenzo Librandi, <a href="/A135039/b135039.txt">Table of n, a(n) for n = 0..1000</a> %t A135039 Ceiling[Pi Range[50]^2] (* _Harvey P. Dale_, Oct 10 2011 *) %Y A135039 Cf. A066643. %K A135039 nonn,easy %O A135039 0,2 %A A135039 _Mohammad K. Azarian_, Feb 29 2008 %E A135039 New name (using explicit formula), _Joerg Arndt_, Feb 19 2013