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 A016184 #18 Jul 15 2018 22:04:00
%S A016184 1,19,277,3667,46405,573667,7001653,84843379,1023885349,12326977795,
%T A016184 148206208789,1780451832211,21379263273733,256648048295203,
%U A016184 3080454802615285,36970205192893363,443675695245289957
%N A016184 Expansion of 1/((1-7x)(1-12x)).
%H A016184 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (19,-84).
%F A016184 a(n) = (12^(n+1) - 7^(n+1))/5. - Lambert Klasen (lambert.klasen(AT)gmx.net), Feb 06 2005
%F A016184 a(n) = 12*a(n-1) + 7^n, a(0)=1. - _Vincenzo Librandi_, Feb 09 2011
%F A016184 a(n) = 19*a(n-1) - 84*a(n-2), a(0)=1, a(1)=19. - _Vincenzo Librandi_, Feb 09 2011
%t A016184 Join[{a=1,b=19},Table[c=19*b-84*a;a=b;b=c,{n,40}]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 14 2011 *)
%t A016184 CoefficientList[Series[1/((1-7x)(1-12x)),{x,0,20}],x] (* or *) LinearRecurrence[ {19,-84},{1,19},20] (* _Harvey P. Dale_, Jul 09 2018 *)
%o A016184 (PARI) Vec(1/((1-7*x)*(1-12*x))+O(x^99)) \\ _Charles R Greathouse IV_, Sep 26 2012
%K A016184 nonn,easy
%O A016184 0,2
%A A016184 _N. J. A. Sloane_