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 A121854 #22 Feb 12 2020 01:56:03
%S A121854 0,3,4,5,6,7,7,8,8,9,9,10,10,11,11,12,12,12,13,13,14,14,14,15,15,15,
%T A121854 16,16,16,16,17,17,17,18,18,18,18,19,19,19,19,20,20,20,20,21,21,21,21,
%U A121854 21,22,22,22,22,23,23,23,23,23,24,24,24
%N A121854 a(n) = floor(Pi*(sqrt(n))).
%H A121854 Vincenzo Librandi, <a href="/A121854/b121854.txt">Table of n, a(n) for n = 0..1000</a>
%t A121854 Table[Floor[\[Pi] Sqrt[n]],{n,0,65}] (* _Harvey P. Dale_, Apr 22 2011 *)
%Y A121854 Cf. A121275, A121276.
%K A121854 nonn,easy
%O A121854 0,2
%A A121854 _Mohammad K. Azarian_, Aug 30 2006
%E A121854 Offset corrected and b-file updated by _Ivan Panchenko_, Nov 13 2013