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 A106251 #8 Oct 04 2021 15:35:21
%S A106251 1,0,1,2,2,3,4,3,4,5,5,6,7,6,7,8,8,9,10,9,10,11,11,12,13,12,13,14,14,
%T A106251 15,16,15,16,17,17,18,19,18,19,20,20,21,22,21,22,23,23,24,25,24,25,26,
%U A106251 26,27,28,27,28,29,29,30,31,30,31,32,32,33,34,33,34,35,35,36,37,36,37,38
%N A106251 Expansion of (1-x+x^2+x^3+x^5)/(1-x-x^6+x^7).
%H A106251 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,1,-1).
%F A106251 G.f.: (1+x^2+2x^3+2x^4+3x^5+2x^6+3x^7+2x^8+x^9+x^10)/(1-x^6)^2; a(n)=sum{k=0..n, -mu(k mod 6)}.
%t A106251 LinearRecurrence[{1,0,0,0,0,1,-1},{1,0,1,2,2,3,4},80] (* _Harvey P. Dale_, Oct 04 2021 *)
%Y A106251 Cf. A008611, A106249, A106250.
%K A106251 easy,nonn
%O A106251 0,4
%A A106251 _Paul Barry_, Apr 27 2005