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 A190248 #34 Jan 05 2025 19:51:39 %S A190248 1,0,2,1,0,1,1,2,1,0,2,1,0,1,1,2,1,0,1,1,2,1,0,2,1,0,1,1,2,1,0,2,1,0, %T A190248 1,0,2,1,0,1,1,2,1,0,2,1,0,1,1,2,1,0,2,1,2,1,0,2,1,0,1,1,2,1,0,2,1,0, %U A190248 1,1,2,1,0,1,1,2,1,0,2,1,0,1,1,2,1,0,2,1,0,1,0,2,1,0,1,1,2,1,0,2,1,0,1,1,2,1,0,1 %N A190248 a(n) = [nu+nv+nw]-[nu]-[nv]-[nw], where u=(1+sqrt(5))/2, v=u^2, w=u^3, []=floor. %C A190248 a(n) = A190440(n) - A078588(n). This follows from substituting w = 1+2u, v = 1+u, and taking 2n, n and n out of the floor functions. - _Michel Dekking_, Oct 21 2016 %H A190248 G. C. Greubel, <a href="/A190248/b190248.txt">Table of n, a(n) for n = 1..10000</a> %H A190248 Burghard Herrmann, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Papers1/57-5/herrmann.pdf">How integer sequences find their way into areas outside pure mathematics</a>, The Fibonacci Quarterly (2019) Vol. 57, No. 5, 67-71. %F A190248 a(n) = [2n+4nu]-[nu]-[n+nu]-[n+2nu], where u=(1+sqrt(5))/2. - _Michel Dekking_, Oct 21 2016 %t A190248 u = GoldenRatio; v = u^2; w=u^3; %t A190248 f[n_] := Floor[n*u + n*v + n*w] - Floor[n*u] - Floor[n*v] - Floor[n*w] %t A190248 t = Table[f[n], {n, 1, 120}] (* A190248 *) %t A190248 Flatten[Position[t, 0]] (* A190249 *) %t A190248 Flatten[Position[t, 1]] (* A190250 *) %t A190248 Flatten[Position[t, 2]] (* A190251 *) %o A190248 (PARI) for(n=1,30, print1(floor(2*n*(2+sqrt(5))) - floor(n*(1+sqrt(5))/2) - floor(n*(3 + sqrt(5))/2) - floor(n*(2 + sqrt(5))), ", ")) \\ _G. C. Greubel_, Dec 26 2017 %o A190248 (Magma) [Floor(2*n*(2+Sqrt(5))) - Floor(n*(1+Sqrt(5))/2) - Floor(n*(3 + Sqrt(5))/2): n in [1..30]]; // _G. C. Greubel_, Dec 26 2017 %Y A190248 Cf. A190249, A190250, A190251. %K A190248 nonn %O A190248 1,3 %A A190248 _Clark Kimberling_, May 06 2011 %E A190248 Name corrected by _Michel Dekking_, Oct 21 2016