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 A091927 #7 Aug 11 2019 14:28:22
%S A091927 1,0,5,30,205,1380,9305,62730,422905,2851080,19221005,129581430,
%T A091927 873593605,5889468780,39704780705,267676028130,1804580072305,
%U A091927 12165860574480,82018063808405,552937685722830,3727716433379005
%N A091927 Expansion of (1-6x)/(1-6x-5x^2).
%C A091927 Let the generating matrix of the Golay G_12 code be [I|B]. Then a(n)=(B^n)_1,1.
%H A091927 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,5).
%F A091927 a(n)=5(sqrt(14)(3+sqrt(14))^(n-1)/28-sqrt(14)(3-sqrt(14))^(n-1)/28)
%t A091927 CoefficientList[Series[(1-6x)/(1-6x-5x^2),{x,0,30}],x] (* or *) LinearRecurrence[ {6,5},{1,0},30](* _Harvey P. Dale_, Aug 11 2019 *)
%Y A091927 Cf. A015551.
%K A091927 easy,nonn
%O A091927 0,3
%A A091927 _Paul Barry_, Feb 13 2004