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 A133873 #9 Apr 16 2023 22:13:11 %S A133873 1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0, %T A133873 0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2, %U A133873 2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2,0,0,0,1,1,1,2,2,2 %N A133873 n modulo 3 repeated 3 times. %C A133873 Periodic with length 3^2=9. %H A133873 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, -1, 1, 0, -1, 1). %F A133873 G.f.: (1 + 2*x^3)*(1 - x^3)/((1 - x)*(1 - x^9)). %F A133873 a(n) = (1 + floor(n/3)) mod 3. %F A133873 a(n) = A010872(A002264(n+3)). %F A133873 a(n) = 1+floor(n/3)-3*floor((n+3)/9). %F A133873 a(n) = (((n+3) mod 9)-(n mod 3))/3. %F A133873 a(n) = ((n+3-(n mod 3))/3) mod 3. %F A133873 a(n) = binomial(n+3,n) mod 3 = binomial(n+3,3) mod 3. %Y A133873 Cf. A000040, A133620-A133625, A133630, A038509, A133634-A133636. %Y A133873 Cf. A133883, A133880, A133890, A133900, A133910. %K A133873 nonn,easy %O A133873 0,4 %A A133873 _Hieronymus Fischer_, Oct 10 2007