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 A098021 #31 Sep 08 2022 08:45:14
%S A098021 5,10,17,22,29,34,39,46,51,58,63,68,75,80,87,92,99,104,109,116,121,
%T A098021 128,133,138,145,150,157,162,169,174,179,186,191,198,203,208,215,220,
%U A098021 227,232,237,244,249,256,261,268,273,278,285,290,297,302,307,314,319,326
%N A098021 Positions of 0's in the zero-one sequence [nr+2r]-[nr]-[2r], where r=sqrt(2) and [ ]=floor; see A187967.
%C A098021 Former definition was "Irrational rotation of the square root of 2 as an implicit sequence with an uneven Cantor cartoon." Replaced this with more precise definition from _Clark Kimberling_. - _N. J. A. Sloane_, Jan 30 2016
%H A098021 G. C. Greubel, <a href="/A098021/b098021.txt">Table of n, a(n) for n = 1..10000</a>
%F A098021 a(n) = 7 * floor(n * (sqrt(2) - 1)) + 5 * floor(n * (2 - sqrt(2))) + 5. - _Miko Labalan_, Dec 14 2015
%F A098021 a(n) = 3*n + 2*floor(n*sqrt(2)). - _G. C. Greubel_, Mar 27 2018
%t A098021 Table[7 Floor[n (Sqrt[2] - 1)] + 5 Floor[n (2 - Sqrt[2])] + 5, {n, 1000}] (* _Miko Labalan_, Dec 14 2015 *)
%t A098021 Table[3*n + 2*Floor[n*Sqrt[2]], {n,1,100}] (* _G. C. Greubel_, Mar 27 2018 *)
%o A098021 (Magma) [3*n+2*Floor(n*Sqrt(2)): n in [1..60]]; // _Vincenzo Librandi_, Dec 17 2015
%o A098021 (PARI) for(n=1,100, print1(3*n + 2*floor(n*sqrt(2)), ", ")) \\ _G. C. Greubel_, Mar 27 2018
%Y A098021 Cf. A187967.
%K A098021 nonn
%O A098021 1,1
%A A098021 _Roger L. Bagula_, Sep 09 2004
%E A098021 Edited and extended by _Robert G. Wilson v_, Sep 25 2004
%E A098021 Entry revised by _N. J. A. Sloane_, Jan 30 2016