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 A083578 #12 Mar 08 2021 12:06:41
%S A083578 1,1,26,76,776,3376,25376,131776,872576,4907776,30757376,179301376,
%T A083578 1096779776,6496792576,39316299776,234555621376,1412702437376,
%U A083578 8454739787776,50814338072576,304542431051776,1828628975845376
%N A083578 a(n) = (6^n + (-4)^n)/2.
%H A083578 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,24).
%F A083578 a(n) = (6^n + (-4)^n)/2.
%F A083578 G.f.: (1-x)/((1+4x)(1-6x)).
%F A083578 E.g.f.: (exp(6x) + exp(-4x))/2.
%t A083578 LinearRecurrence[{2,24},{1,1},30] (* _Harvey P. Dale_, Nov 29 2017 *)
%Y A083578 Cf. A083579. First differences of A051958.
%K A083578 easy,nonn
%O A083578 0,3
%A A083578 _Paul Barry_, Apr 30 2003