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 A190489 #8 Jul 03 2017 02:09:19
%S A190489 1,4,6,11,13,16,18,23,25,28,30,35,40,42,45,47,52,54,57,59,64,66,69,71,
%T A190489 74,76,81,83,86,88,93,95,98,100,103,105,110,112,115,117,122,124,127,
%U A190489 129,134,139,141,144,146,151,153,156,158,163,165,168,170,173,175,180,182,185,187,192,194,197,199,204,209,211,214,216,221,223
%N A190489 Positions of 1 in A190487.
%H A190489 G. C. Greubel, <a href="/A190489/b190489.txt">Table of n, a(n) for n = 1..1000</a>
%t A190489 r = Sqrt[2]; b = 3; c = 0;
%t A190489 f[n_] := Floor[(b*n + c)*r] - b*Floor[n*r] - Floor[c*r];
%t A190489 t = Table[f[n], {n, 1, 200}] (* A190487 *)
%t A190489 Flatten[Position[t, 0]] (* A190488 *)
%t A190489 Flatten[Position[t, 1]] (* A190489 *)
%t A190489 Flatten[Position[t, 2]] (* A190490 *)
%Y A190489 Cf. A190487.
%K A190489 nonn
%O A190489 1,2
%A A190489 _Clark Kimberling_, May 11 2011