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 A212443 #9 Aug 22 2023 07:59:38
%S A212443 4,16,64,280,1344,6496,32640,166320,862400,4523232,23970240,128063040,
%T A212443 689008320,3728973120,20285199872,110841302880,608029121280,
%U A212443 3346972244000,18480871268160,102328688556864,568014587806720,3160148362953120,17617881702072960
%N A212443 a(n) = (1/n) * Sum_{d|n} moebius(n/d) * A002203(d)^2, where A002203 is the companion Pell numbers.
%F A212443 G.f.: 1/Product_{n>=1} (1 - A002203(n)*x^n + (-1)^n*x^(2*n))^a(n) = exp(Sum_{n>=1} A002203(n)^3 * x^n/n), which equals the g.f. of A212442.
%t A212443 a[n_] := DivisorSum[n, MoebiusMu[n/#] * LucasL[#, 2]^2 &] / n; Array[a, 25] (* _Amiram Eldar_, Aug 22 2023 *)
%o A212443 (PARI) {A002203(n)=polcoeff(2*x*(1+x)/(1-2*x-x^2+x*O(x^n)),n)}
%o A212443 {a(n)=if(n<1, 0, sumdiv(n, d, moebius(n/d)*A002203(d)^2)/n)}
%o A212443 for(n=1,30,print1(a(n),","))
%Y A212443 Cf. A008683, A212442, A203853, A002203.
%K A212443 nonn
%O A212443 1,1
%A A212443 _Paul D. Hanna_, May 17 2012