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 A164591 #20 Jul 10 2022 09:42:32
%S A164591 1,7,48,328,2240,15296,104448,713216,4870144,33255424,227082240,
%T A164591 1550614528,10588258304,72301150208,493703135232,3371215880192,
%U A164591 23020101959680,157191088635904,1073367893409792,7329414438191104,50048372358250496
%N A164591 a(n) = ((4 + sqrt(18))*(4 + sqrt(8))^n + (4 - sqrt(18))*(4 - sqrt(8))^n)/8 .
%C A164591 Binomial transform of A001109 without initial 0. Fourth binomial transform of A096886. Inverse binomial transform of A164592.
%H A164591 G. C. Greubel, <a href="/A164591/b164591.txt">Table of n, a(n) for n = 0..1000</a> (terms 0..100 from Vincenzo Librandi)
%H A164591 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,-8).
%F A164591 a(n) = 8*a(n-1) - 8*a(n-2) for n > 1; a(0) = 1, a(1) = 7.
%F A164591 G.f.: (1-x)/(1-8*x+8*x^2).
%F A164591 E.g.f.: (1/4)*exp(4*x)*(4*cosh(2*sqrt(2)*x) + 3*sqrt(2)*sinh(2*sqrt(2)*x)). - _G. C. Greubel_, Aug 12 2017
%t A164591 LinearRecurrence[{8,-8}, {1,7}, 50] (* _G. C. Greubel_, Aug 12 2017 *)
%o A164591 (Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((4+3*r)*(4+2*r)^n+(4-3*r)*(4-2*r)^n)/8: n in [0..19] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Aug 24 2009
%o A164591 (PARI) Vec((1-x)/(1-8*x+8*x^2)+O(x^99)) \\ _Charles R Greathouse IV_, Jul 16 2011
%Y A164591 Cf. A001109, A096886, A164592.
%K A164591 nonn,easy
%O A164591 0,2
%A A164591 Al Hakanson (hawkuu(AT)gmail.com), Aug 17 2009
%E A164591 Extended by _Klaus Brockhaus_ and _R. J. Mathar_ Aug 24 2009