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 A172474 #22 Sep 08 2022 08:45:50
%S A172474 0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,5,6,6,6,7,7,7,8,8,8,9,9,9,10,10,10,
%T A172474 11,11,12,12,12,13,13,13,14,14,14,15,15,15,16,16,16,17,17,18,18,18,19,
%U A172474 19,19,20,20,20,21,21,21,22,22,22,23,23,24,24,24,25,25,25,26,26
%N A172474 a(n) = floor(n*sqrt(2)/4).
%H A172474 Vincenzo Librandi, <a href="/A172474/b172474.txt">Table of n, a(n) for n = 0..1000</a>
%p A172474 a:=n->floor(n*sqrt(2)/4): seq(a(n),n=0..80); # _Muniru A Asiru_, Sep 28 2018
%t A172474 Table[Floor[n Sqrt[2]/4], {n, 0, 80}] (* _Vincenzo Librandi_, Aug 01 2013 *)
%o A172474 (Magma) [Floor(n*Sqrt(2)/4): n in [0..80]]; // _Vincenzo Librandi_, Aug 01 2013
%o A172474 (PARI) vector(80, n, n--; floor(n*sqrt(2)/4)) \\ _G. C. Greubel_, Sep 28 2018
%Y A172474 Cf. A022842: floor(n/(sqrt(2)/4)).
%K A172474 nonn,easy
%O A172474 0,7
%A A172474 _Vincenzo Librandi_, Feb 04 2010