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 A091087 #8 Sep 08 2022 08:45:12
%S A091087 0,1,3,6,7,10,12,13,16,18,21,22,24,27,28,31,33,36,37,39,42,43,46,48,
%T A091087 49,52,54,57,58,61,63,64,67,69,72,73,75,78,79,82,84,85,88,90,93,94,97,
%U A091087 99,100,103,105,108,109,111,114,115,118,120,123,124,126,129,130,133,135
%N A091087 a(n) = floor(r*n) + floor(n/r), where r=sqrt(2).
%H A091087 G. C. Greubel, <a href="/A091087/b091087.txt">Table of n, a(n) for n = 0..10000</a>
%t A091087 Table[Floor[n*Sqrt[2]] + Floor[n/Sqrt[2]], {n, 0, 100}] (* _G. C. Greubel_, Sep 27 2018 *)
%o A091087 (PARI) vector(100, n, n--; floor(n*sqrt(2)) + floor(n/sqrt(2))) \\ _G. C. Greubel_, Sep 27 2018
%o A091087 (Magma) [Floor(n*Sqrt(2)) + Floor(n/Sqrt(2)): n in [0..100]]; // _G. C. Greubel_, Sep 27 2018
%Y A091087 Cf. A049473.
%K A091087 nonn
%O A091087 0,3
%A A091087 _Clark Kimberling_, Dec 18 2003