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 A321573 #15 Jul 01 2023 16:25:14 %S A321573 1,2,8,22,68,202,608,1822,5468,16402,49208,147622,442868,1328602, %T A321573 3985808,11957422,35872268,107616802,322850408,968551222,2905653668, %U A321573 8716961002,26150883008,78452649022,235357947068,706073841202,2118221523608,6354664570822,19063993712468 %N A321573 Row sums of A321624. %H A321573 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2, 3). %F A321573 From _Philippe Deléham_, Feb 05 2020: (Start) %F A321573 G.f.: (1+x^2)/(1-2x-3*x^2). %F A321573 a(0)=1, a(1)=2, a(2)=8, a(n)=2*a(n-1)+3*a(n-2) , for n>2. %F A321573 a(0)=1, a(n) = (5*3^(n-1)-(-1)^(n-1))/2, for n>0 . (End) %t A321573 (* The function RiordanSquare is defined in A321620. *) %t A321573 Lucas = 1 + x*(1 + 2x)/(1 - x - x^2); %t A321573 M = RiordanSquare[Lucas, 29]; Map[Total, M] %Y A321573 Cf. A321624, A321620. %K A321573 nonn %O A321573 0,2 %A A321573 _Peter Luschny_, Nov 22 2018