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 A012493 #25 Aug 20 2025 00:29:04
%S A012493 0,2,9,37,151,616,2513,10252,41824,170625,696081,2839729,11584946,
%T A012493 47261895,192809420,786584466,3208946545,13091204281,53406819691,
%U A012493 217878227876,888855064897,3626169232672,14793304131648,60350698792449,246206446668325,1004422742303477
%N A012493 Take every 5th term of Padovan sequence A000931, beginning with the fifth term.
%H A012493 Vincenzo Librandi, <a href="/A012493/b012493.txt">Table of n, a(n) for n = 0..1000</a>
%H A012493 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-4,1).
%F A012493 a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
%F A012493 G.f.: x*(2-x)/(1-5*x+4*x^2-x^3). - _Colin Barker_, Feb 02 2012
%t A012493 CoefficientList[Series[x*(2-x)/(1-5*x+4*x^2-x^3),{x,0,30}],x] (* _Vincenzo Librandi_, Apr 17 2012 *)
%t A012493 LinearRecurrence[{5,-4,1},{0,2,9},30] (* _Harvey P. Dale_, Nov 24 2018 *)
%o A012493 (Magma) I:=[0, 2, 9]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..30]]; // _Vincenzo Librandi_, Apr 17 2012
%K A012493 nonn,easy
%O A012493 0,2
%A A012493 _N. J. A. Sloane_
%E A012493 First term corrected by _Colin Barker_, Feb 02 2012