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 A081627 #10 Sep 08 2022 08:45:09
%S A081627 1,9,73,561,4177,30489,219673,1568961,11138977,78754089,555184873,
%T A081627 3905825361,27438433777,192557317689,1350342630073,9464605441761,
%U A081627 66313273248577,464498088521289,3253012498555273,22778716884418161
%N A081627 2*7^n-5^n.
%C A081627 Binomial transform of A081626.
%H A081627 Vincenzo Librandi, <a href="/A081627/b081627.txt">Table of n, a(n) for n = 0..1000</a>
%H A081627 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (12,-35).
%F A081627 G.f.: (1-3*x)/((1-5*x)*(1-7*x)).
%F A081627 E.g.f. 2*exp(7*x)-exp(5*x).
%t A081627 CoefficientList[Series[(1 - 3 x) / ((1 - 5 x) (1 - 7 x)), {x, 0, 40}], x] (* _Vincenzo Librandi_, Aug 09 2013 *)
%o A081627 (Magma) [2*7^n-5^n: n in [0..25]]; // _Vincenzo Librandi_, Aug 09 2013
%K A081627 easy,nonn
%O A081627 0,2
%A A081627 _Paul Barry_, Mar 25 2003