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 A163070 #24 Sep 08 2022 08:45:46
%S A163070 4,13,56,237,1004,4253,18016,76317,323284,1369453,5801096,24573837,
%T A163070 104096444,440959613,1867934896,7912699197,33518731684,141987625933,
%U A163070 601469235416,2547864567597,10792927505804,45719574590813
%N A163070 a(n) = ((4+sqrt(5))*(2+sqrt(5))^n + (4-sqrt(5))*(2-sqrt(5))^n)/2.
%C A163070 Binomial transform of A163069. Second binomial transform of A163141. Inverse binomial transform of A163071.
%H A163070 G. C. Greubel, <a href="/A163070/b163070.txt">Table of n, a(n) for n = 0..1000</a>
%H A163070 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4,1).
%F A163070 a(n) = 4*a(n-1) + a(n-2) for n > 1; a(0) = 4, a(1) = 13.
%F A163070 G.f.: (4-3*x)/(1-4*x-x^2).
%F A163070 a(n) = 2*A000032(3*n) + 5*A000045(3*n)/2 = 2*A014448(n) + 5*A001076(n). - _Diego Rattaggi_, Aug 09 2020
%t A163070 LinearRecurrence[{4,1},{4,13},30] (* _Harvey P. Dale_, Sep 19 2011 *)
%o A163070 (Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-5); S:=[ ((4+r)*(2+r)^n+(4-r)*(2-r)^n)/2: n in [0..21] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Jul 21 2009
%o A163070 (PARI) x='x+O('x^30); Vec((4-3*x)/(1-4*x-x^2)) \\ _G. C. Greubel_, Jan 08 2018
%Y A163070 Cf. A000032, A000045, A001076, A014448, A163069, A163071, A163141.
%K A163070 nonn
%O A163070 0,1
%A A163070 Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009
%E A163070 Edited and extended beyond a(5) by _Klaus Brockhaus_, Jul 21 2009