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 A161941 #18 Sep 08 2022 08:45:45
%S A161941 2,5,16,54,184,628,2144,7320,24992,85328,291328,994656,3395968,
%T A161941 11594560,39586304,135156096,461451776,1575494912,5379076096,
%U A161941 18365314560,62703106048,214081795072,730920968192,2495520282624,8520239194112
%N A161941 a(n) = ((4+sqrt(2))*(2+sqrt(2))^n + (4-sqrt(2))*(2-sqrt(2))^n)/4.
%C A161941 Second binomial transform of A135530.
%H A161941 G. C. Greubel, <a href="/A161941/b161941.txt">Table of n, a(n) for n = 0..1000</a>
%H A161941 C. Bautista-Ramos and C. Guillen-Galvan, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL15/Bautista/bautista4.html">Fibonacci numbers of generalized Zykov sums</a>, J. Integer Seq., 15 (2012), #12.7.8.
%H A161941 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4, -2).
%F A161941 a(n) = 4*a(n-1) - 2*a(n-2) for n>1; a(0) = 2; a(1) = 5.
%F A161941 G.f.: (2-3*x)/(1-4*x+2*x^2).
%F A161941 a(n) = 2*A007070(n) - 3*A007070(n-1). - _R. J. Mathar_, Oct 20 2017
%t A161941 LinearRecurrence[{4,-2},{2,5},30] (* _Harvey P. Dale_, May 26 2012 *)
%o A161941 (Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((4+r)*(2+r)^n+(4-r)*(2-r)^n)/4: n in [0..24] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Jul 01 2009
%o A161941 (PARI) x='x+O('x^30); Vec((2-3*x)/(1-4*x+2*x^2)) \\ _G. C. Greubel_, Jan 27 2018
%Y A161941 Cf. A135530, A161944 (third binomial transform of A135530).
%K A161941 nonn,easy
%O A161941 0,1
%A A161941 Al Hakanson (hawkuu(AT)gmail.com), Jun 22 2009
%E A161941 Edited and extended beyond a(4) by _Klaus Brockhaus_, Jul 01 2009