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 A172475 #14 Sep 08 2022 08:45:50
%S A172475 0,0,1,2,3,4,5,6,6,7,8,9,10,11,12,12,13,14,15,16,17,18,19,19,20,21,22,
%T A172475 23,24,25,25,26,27,28,29,30,31,32,32,33,34,35,36,37,38,38,39,40,41,42,
%U A172475 43,44,45,45,46,47,48,49,50,51,51,52,53,54,55,56,57,58,58,59,60,61,62
%N A172475 a(n) = floor(n*sqrt(3)/2).
%H A172475 Vincenzo Librandi, <a href="/A172475/b172475.txt">Table of n, a(n) for n = 0..1000</a>
%F A172475 a(n) = A171970(n). [_R. J. Mathar_, Feb 05 2010]
%t A172475 With[{c = Sqrt[3]/2}, Floor[c #] &/@ Range[0, 90]] (* _Harvey P. Dale_, Feb 07 2011 *)
%o A172475 (Magma) [Floor(n*Sqrt(3)/2): n in [0..80]]; // _Vincenzo Librandi_, Aug 01 2013
%K A172475 nonn,easy
%O A172475 0,4
%A A172475 _Vincenzo Librandi_, Feb 04 2010