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 A189678 #6 Mar 08 2020 18:10:20
%S A189678 5,10,16,21,26,32,38,44,49,54,60,65,72,77,82,88,93,98,104,110,116,121,
%T A189678 126,132,137,144,149,154,160,165,171,177,182,188,193,198,204,209,216,
%U A189678 221,226,232,237,243,249,254,260,265,271,276,281,288,293,298,304,309,315,321,326,332,337,343,348,354,360,365,370,376,381,387,393,398,404,409,415,420,426,432,437,443,448,453
%N A189678 n+[nr/s]+[nt/s]; r=1, s=arctan(1/2), t=arctan(2).
%C A189678 See A189677.
%t A189678 (See A189677.)
%t A189678 Table[n+Floor[n/ArcTan[1/2]]+Floor[(n*ArcTan[2])/ArcTan[1/2]],{n,90}] (* _Harvey P. Dale_, Mar 08 2020 *)
%Y A189678 Cf. A189677, A189679.
%K A189678 nonn
%O A189678 1,1
%A A189678 _Clark Kimberling_, Apr 25 2011