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 A121857 #15 Aug 09 2015 02:19:14
%S A121857 0,3,4,5,6,7,7,8,8,9,9,10,10,10,11,11,11,12,12,12,13,13,13,14,14,14,
%T A121857 14,15,15,15,15,16,16,16,16,17,17,17,17,17,18,18,18,18,19,19,19,19,19,
%U A121857 20,20,20,20,20,20,21,21,21,21,21,22,22,22,22,22,22,23,23,23,23,23,23,24
%N A121857 a(n) = ceiling(e*sqrt(n)).
%H A121857 Vincenzo Librandi, <a href="/A121857/b121857.txt">Table of n, a(n) for n = 0..1000</a> (indices changed and term 1000 added by Ivan Panchenko)
%t A121857 Table[Ceiling[E Sqrt[n]], {n, 0, 80}] (* _Vincenzo Librandi_, Feb 21 2013 *)
%K A121857 nonn,easy
%O A121857 0,2
%A A121857 _Mohammad K. Azarian_, Aug 30 2006
%E A121857 Offset corrected by _Ivan Panchenko_, Nov 13 2013