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 A179753 #8 Jun 06 2025 14:47:13
%S A179753 1,0,3,2,1,0,5,4,3,2,1,0,7,6,5,4,3,2,1,0,9,8,7,6,5,4,3,2,1,0,11,10,9,
%T A179753 8,7,6,5,4,3,2,1,0,13,12,11,10,9,8,7,6,5,4,3,2,1,0,15,14,13,12,11,10,
%U A179753 9,8,7,6,5,4,3,2,1,0,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0
%N A179753 Integers (2k)-1..0 followed by integers (2k)+1..0 and so on.
%F A179753 a(n) = (2*A000194(n)) - A074294(n).
%t A179753 Flatten[Table[Range[2n-1,0,-1],{n,10}]] (* _Harvey P. Dale_, Oct 08 2012 *)
%o A179753 (Python)
%o A179753 from math import isqrt
%o A179753 def A179753(n): return (k:=(m:=isqrt(n))+(n>m*(m+1)))*(1+k)-n # _Chai Wah Wu_, Jun 06 2025
%K A179753 nonn
%O A179753 1,3
%A A179753 _Antti Karttunen_, Aug 03 2010