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 A047556 #16 Sep 02 2024 12:21:51
%S A047556 3,6,7,11,14,15,19,22,23,27,30,31,35,38,39,43,46,47,51,54,55,59,62,63,
%T A047556 67,70,71,75,78,79,83,86,87,91,94,95,99,102,103,107,110,111,115,118,
%U A047556 119,123,126,127,131,134,135,139,142,143,147,150,151,155,158,159
%N A047556 Numbers that are congruent to {3, 6, 7} mod 8.
%H A047556 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,1,-1).
%F A047556 G.f.: x*(1+x)*(x^2+3) / ((1+x+x^2)*(x-1)^2). - _R. J. Mathar_, Oct 08 2011
%F A047556 From _Wesley Ivan Hurt_, Jun 10 2016: (Start)
%F A047556 a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
%F A047556 a(n) = (24*n-9*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9.
%F A047556 a(3k) = 8k-1, a(3k-1) = 8k-2, a(3k-2) = 8k-5. (End)
%p A047556 A047556:=n->(24*n-9*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9: seq(A047556(n), n=1..100); # _Wesley Ivan Hurt_, Jun 10 2016
%t A047556 Select[Range[0, 150], MemberQ[{3, 6, 7}, Mod[#, 8]] &] (* _Wesley Ivan Hurt_, Jun 10 2016 *)
%t A047556 LinearRecurrence[{1,0,1,-1},{3,6,7,11},60] (* _Harvey P. Dale_, Sep 02 2024 *)
%o A047556 (Magma) [n : n in [0..150] | n mod 8 in [3, 6, 7]]; // _Wesley Ivan Hurt_, Jun 10 2016
%K A047556 nonn,easy
%O A047556 1,1
%A A047556 _N. J. A. Sloane_