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 A172471 #29 May 23 2025 10:21:06
%S A172471 0,1,2,2,2,3,3,3,4,4,4,4,4,5,5,5,5,5,6,6,6,6,6,6,6,7,7,7,7,7,7,7,8,8,
%T A172471 8,8,8,8,8,8,8,9,9,9,9,9,9,9,9,9,10,10,10,10,10,10,10,10,10,10,10,11,
%U A172471 11,11,11,11,11,11,11,11,11,11,12,12,12
%N A172471 a(n) = floor(sqrt(2*n)).
%C A172471 If k is even, k appears k+1 times; if k is odd, k appears k times. - _N. J. A. Sloane_, Jan 25 2021
%H A172471 N. J. A. Sloane, <a href="/A172471/b172471.txt">Table of n, a(n) for n = 0..20000</a> [First 10000 terms from Vincenzo Librandi]
%F A172471 a(n) = A000196(2*n). - _R. J. Mathar_, Jul 06 2010
%t A172471 Table[Floor[Sqrt[2n]],{n,0,80}]
%o A172471 (Magma) [Floor(Sqrt(2*n)) : n in [0..80]];
%o A172471 (Haskell)
%o A172471 a172471 = a000196 . (* 2) -- _Reinhard Zumkeller_, Feb 12 2012
%o A172471 (PARI) a(n) = sqrtint(2*n); \\ _Michel Marcus_, May 23 2025
%Y A172471 Cf. A000196, A003056, A103128, A005843.
%K A172471 nonn,easy
%O A172471 0,3
%A A172471 _Vincenzo Librandi_, Feb 04 2010