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 A133893 #4 Aug 27 2023 15:38:25 %S A133893 6,7,8,15,16,17,24,25,26,33,34,35,42,43,44,51,52,53,60,61,62,69,70,71, %T A133893 78,79,80,87,88,89,96,97,98,105,106,107,114,115,116,123,124,125,132, %U A133893 133,134,141,142,143,150,151,152,159,160,161,168,169,170,177,178,179,186 %N A133893 Numbers m such that binomial(m+3,m) mod 3 = 0. %C A133893 Also numbers m such that floor(1+(m/3)) mod 3 = 0. %C A133893 Partial sums of the sequence 6,1,1,7,1,1,7,1,1,7, ... which has period 3. %F A133893 a(n)=3n+6-2*(n mod 3). %F A133893 G.f.: g(x)=6/(1-x)+x(1+x+7x^2)/((1-x^3)(1-x)) = (6+x+x^2+x^3)/((1-x^3)(1-x)). %F A133893 G.f.: g(x)=(6-5x-x^4)/((1-x^3)(1-x)^2). %t A133893 Select[Range[200],Mod[Binomial[#+3,#],3]==0&] (* _Harvey P. Dale_, Aug 27 2023 *) %Y A133893 Cf. A000040, A133620, A133621, A133623, A133630, A133635. %Y A133893 Cf. A133873, A133883, A133890, A133900, A133910. %K A133893 nonn %O A133893 0,1 %A A133893 _Hieronymus Fischer_, Oct 20 2007