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 A093144 #14 Aug 04 2021 16:18:20
%S A093144 0,1,20,350,6000,102500,1750000,29875000,510000000,8706250000,
%T A093144 148625000000,2537187500000,43312500000000,739390625000000,
%U A093144 12622187500000000,215474218750000000,3678375000000000000
%N A093144 Third binomial transform of Pell(3*n)/Pell(3).
%H A093144 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (20,-50).
%F A093144 G.f.: x/(1-20*x+50*x^2);
%F A093144 a(n) = ((10 + 5*sqrt(2))^n - (10 - 5*sqrt(2))^n)/(10*sqrt(2)).
%t A093144 LinearRecurrence[{20,-50},{0,1},30] (* _Harvey P. Dale_, Aug 04 2021 *)
%Y A093144 Cf. A000129, A041085.
%K A093144 easy,nonn
%O A093144 0,3
%A A093144 _Paul Barry_, Mar 26 2004