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 A289006 #24 Jun 29 2017 05:20:13
%S A289006 0,1,3,6,15,33,66,155,333,666,1555,3333,6666,15555,33333,66666,155555,
%T A289006 333333,666666,1555555,3333333,6666666,15555555,33333333,66666666,
%U A289006 155555555,333333333,666666666,1555555555,3333333333,6666666666,15555555555,33333333333,66666666666,155555555555,333333333333,666666666666
%N A289006 Conversion to octal of the binary expansion given by the first n terms of the period-3 sequence A011655 (repeat 0, 1, 1).
%C A289006 The length of the n-th term is floor((n+1)/3) digits, for all n>1. [Corrected by _M. F. Hasler_, Jun 23 2017]
%H A289006 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 11, 0, 0, -10).
%F A289006 a(3n) = floor(10^n/3) (= n times the digit '3'), a(3n+1) = floor(10^n/3)*2 (= n times the digit '6'), a(3n+2) = floor(10^(n+1)/6) - floor(10^n/9) (= digit '1' followed by n digits '5'). - _M. F. Hasler_, Jun 23 2017
%F A289006 G.f.: x^2*(1+x)*(4*x^2+2*x+1) / ( (x-1)*(1+x+x^2)*(10*x^3-1) ). - _R. J. Mathar_, Jun 29 2017
%o A289006 (PARI) { my(x='x+O('x^33)); concat([0],Vec( x*(1+x)*(1+2*x+4*x^2)/((1-x)*(1+x+x^2)*(1-10*x^3)) )) } \\ _Joerg Arndt_, Jun 21 2017
%o A289006 (PARI) A289006(n)=if(n%3==2,10^(n\3+1)\6-10^(n\3)\9,10^(n\3)\3<<(n%3)) \\ _M. F. Hasler_, Jun 23 2017
%Y A289006 A033129(n-1) written in base 8.
%Y A289006 Cf. A011655. Trisections: A099915, A002277, A002280.
%K A289006 nonn,base,easy
%O A289006 1,3
%A A289006 _Peter Schonefeld_, Jun 21 2017