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 A016217 #24 Jul 08 2025 05:43:59
%S A016217 1,16,205,2500,30121,361816,4342885,52117900,625424641,7505125216,
%T A016217 90061591165,1080739359700,12968873113561,155626479754216,
%U A016217 1867517764225045,22410213192223900,268922558371256881,3227070700648792816,38724848408366644525,464698180902143126500
%N A016217 Expansion of 1 / ((1-x) * (1-3*x) * (1-12*x)).
%H A016217 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (16, -51, 36).
%F A016217 a(0)=1, a(1)=16, a(n)=15*a(n-1)-36*a(n-2)+1. - _Vincenzo Librandi_, Feb 10 2011
%F A016217 a(0)=1, a(1)=16, a(2)=205, a(n)=16*a(n-1)-51*a(n-2)+36*a(n-3). - _Harvey P. Dale_, May 06 2012
%F A016217 a(n) = 1/22-(1/2)*3^n+(16/11)*12^n. - _Antonio Alberto Olivares_, May 12 2012
%p A016217 a:= n-> add((12^(n+1-j)-3^(n+1-j))/9, j=0..n): seq(a(n), n=0..20); # _Zerinvary Lajos_, Jan 12 2007
%t A016217 CoefficientList[Series[1/((1-x)(1-3x)(1-12x)),{x,0,30}],x] (* or *) LinearRecurrence[{16,-51,36},{1,16,205},30] (* _Harvey P. Dale_, May 06 2012 *)
%K A016217 nonn
%O A016217 0,2
%A A016217 _N. J. A. Sloane_