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 A200540 #11 Mar 30 2012 18:37:32
%S A200540 1,2,10,48,261,1470,8619,51816,318155,1985630,12561308,80360280,
%T A200540 519013571,3379514970,22161470850,146227235904,970126550763,
%U A200540 6467496499590,43304243215638,291087137589552,1963598081845335,13288619577124122,90195242361688863,613843707553183800
%N A200540 Product of Pell and Motzkin numbers: a(n) = A000129(n+1)*A001006(n).
%C A200540 The g.f. for the Pell numbers is 1/(1-2*x-x^2) and the g.f. M(x) for the Motzkin numbers satisfy: M(x) = 1 + x*M(x) + x^2*M(x)^2.
%e A200540 G.f.: A(x) = 1 + 2*x + 10*x^2 + 48*x^3 + 261*x^4 + 1470*x^5 + 8619*x^6 +...
%e A200540 where A(x) = 1*1 + 2*1*x + 5*2*x^2 + 12*4*x^3 + 29*9*x^4 + 70*21*x^5 + 169*51*x^6 + 408*127*x^7 + 985*323*x^8 +...+ A000129(n+1)*A001006(n)*x^n +...
%o A200540 (PARI) {A001006(n)=polcoeff((1-x-sqrt((1-x)^2-4*x^2+x^3*O(x^n)))/(2*x^2),n)}
%o A200540 {A000129(n)=polcoeff( x/(1-2*x-x^2+x*O(x^n)),n)}
%o A200540 {a(n)=A000129(n+1)*A001006(n)}
%Y A200540 Cf. A098616, A200538, A200539, A098614.
%K A200540 nonn
%O A200540 0,2
%A A200540 _Paul D. Hanna_, Nov 18 2011