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 A020341 #21 Dec 17 2024 15:23:28
%S A020341 1,24,397,5652,74665,946992,11736613,143526444,1741517569,21034565640,
%T A020341 253379036989,3047347017156,36615998359513,439728040092768,
%U A020341 5279095003079125,63365680208288988,760504096286734897
%N A020341 Expansion of 1/((1-5x)(1-7x)(1-12x)).
%H A020341 Vincenzo Librandi, <a href="/A020341/b020341.txt">Table of n, a(n) for n = 0..200</a>
%H A020341 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (24,-179,420)
%F A020341 a(n) = 5^(n+2)/14 -7^(n+2)/10 +12^(n+2)/35. - _R. J. Mathar_, Mar 15 2011
%F A020341 a(0)=1, a(1)=24, a(2)=397, a(n)=24*a(n-1)-179*a(n-2)+420*a(n-3). [_Harvey P. Dale_, Dec 10 2011]
%F A020341 a(n) = 19*a(n-1) -84*a(n-2) +5^n. - _Vincenzo Librandi_, Jul 03 2013
%t A020341 CoefficientList[Series[1/((1-5x)(1-7x)(1-12x)),{x,0,30}],x] (* or *) LinearRecurrence[{24,-179,420},{1,24,397},30] (* _Harvey P. Dale_, Dec 10 2011 *)
%o A020341 (Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-5*x)*(1-7*x)*(1-12*x)))); // _Vincenzo Librandi_, Jul 03 2013
%o A020341 (Magma) I:=[1, 24, 397]; [n le 3 select I[n] else 24*Self(n-1)-179*Self(n-2)+420*Self(n-3): n in [1..20]]; // _Vincenzo Librandi_, Jul 03 2013
%K A020341 nonn,easy
%O A020341 0,2
%A A020341 _N. J. A. Sloane_