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 A349707 #22 Dec 25 2021 02:42:01
%S A349707 0,1,4,6,8,10,11,12,13,16,18,20,22,23,24,25,28,30,32,34,35,36,37,40,
%T A349707 42,44,46,47,48,49,52,54,56,58,59,60,61,64,66,68,70,71,72,73,76,78,80,
%U A349707 82,83,84,85,88,90,92,94,95,96,97,100,102,104,106,107,108,109
%N A349707 Numbers that are congruent to {0, 1, 4, 6, 8, 10, 11} (mod 12).
%C A349707 Terms are the key numbers of the pitches of an Enigmatic scale on a standard chromatic keyboard, with root = 0.
%H A349707 Wikipedia, <a href="https://en.wikipedia.org/wiki/Enigmatic_scale">Enigmatic scale</a>.
%H A349707 <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 A349707 G.f.: x^2*(1 + 3*x + 2*x^2 + 2*x^3 + 2*x^4 + x^5 + x^6)/((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)). - _Stefano Spezia_, Dec 01 2021
%F A349707 a(n) = a(n-7) + 12 for n >= 8. - _Michael S. Branicky_, Dec 02 2021
%t A349707 upto=200;Select[Range[0,upto],MemberQ[{0,1,4,6,8,10,11},Mod[#,12]]&] (* _Paolo Xausa_, Nov 30 2021 *)
%t A349707 nterms=100;LinearRecurrence[{1,0,0,0,0,0,1,-1},{0,1,4,6,8,10,11,12},nterms] (* _Paolo Xausa_, Nov 30 2021 *)
%o A349707 (Python)
%o A349707 def a(n): return 12*((n-1)//7) + [0, 1, 4, 6, 8, 10, 11][(n-1)%7]
%o A349707 print([a(n) for n in range(1, 66)]) # _Michael S. Branicky_, Dec 02 2021
%Y A349707 Cf. A083028.
%K A349707 nonn,easy
%O A349707 1,3
%A A349707 _Roberto Bertocco_, Nov 26 2021