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 A191276 #23 Mar 24 2019 11:09:10
%S A191276 0,1,4,5,7,8,11,12,13,16,17,19,20,23,24,25,28,29,31,32,35,36,37,40,41,
%T A191276 43,44,47,48,49,52,53,55,56,59,60,61,64,65,67,68,71,72,73,76,77,79,80,
%U A191276 83,84,85,88,89,91,92,95,96,97,100,101,103,104,107,108,109,112,113,115,116,119,120,121,124,125,127,128,131,132,133,136,137,139,140,143,144,145,148,149,151,152,155,156,157,160,161,163,164,167,168,169,172,173,175,176,179,180,181
%N A191276 Numbers that are congruent to {0, 1, 4, 5, 7, 9, 11} mod 12.
%C A191276 The key-numbers of the pitches of a double harmonic scale (note also as Arabic or Byzantine) on a standard chromatic keyboard, with root = 0.
%H A191276 Wikipedia, <a href="http://en.wikipedia.org/wiki/Double_harmonic_scale">Arabic scale</a>
%H A191276 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,1,-1).
%F A191276 a(n) = a(n-1) + a(n-7) - a(n-8) for n>8.
%F A191276 G.f.: x^2*(1 + x + x^2)*(1 + 2x - 2x^2 + 2x^3 + x^4)/((1-x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)). - _Colin Barker_, Mar 11 2012
%t A191276 LinearRecurrence[{1,0,0,0,0,0,1,-1},{0,1,4,5,7,8,11,12},120] (* _Harvey P. Dale_, Mar 24 2019 *)
%o A191276 (PARI) concat(0,Vec((1+x+x^2)*(1+2*x-2*x^2+2*x^3+x^4)/(1-x)^2/(1+x+x^2+x^3+x^4+x^5+x^6)+O(x^99))) \\ _Charles R Greathouse IV_, Mar 11 2012
%Y A191276 Cf. A190785.
%K A191276 nonn,easy
%O A191276 1,3
%A A191276 _Roberto Bertocco_, May 29 2011