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 A234369 #9 Nov 01 2022 15:23:33
%S A234369 0,1,1,2,4,5,7,9,11,13,16,18,21,24,27,30,33,37,41,44,48,53,57,61,66,
%T A234369 71,76,81,86,91,97,102,108,114,120,126,132,139,145,152,159,166,173,
%U A234369 180,187,195,202,210,218,226,234,242,251,259,268,277,286,295,304,313,323,332
%N A234369 Floor(AGM(1, triangular(n))), where AGM denotes the arithmetic-geometric mean.
%F A234369 a(n) ~ Pi*n^2/(8*log(n) + 4*log(2)). - _Vaclav Kotesovec_, May 09 2016
%t A234369 Table[Floor[ArithmeticGeometricMean[1, n*(n+1)/2]], {n, 0, 100}] (* _Vaclav Kotesovec_, May 09 2016 *)
%t A234369 Floor[ArithmeticGeometricMean[1,#]]&/@Accumulate[Range[0,100]] (* _Harvey P. Dale_, Nov 01 2022 *)
%Y A234369 Cf. A000217, A127758, A234363, A234368.
%K A234369 nonn
%O A234369 0,4
%A A234369 _Alex Ratushnyak_, Dec 25 2013