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 A278681 #4 Nov 27 2016 21:46:47
%S A278681 3,16,85,451,2392,12686,67280,356818,1892376,10036172,53226604,
%T A278681 282286052,1497097488,7939821584,42108658448,223322287224,
%U A278681 1184384537744,6281355751296,33313023614352,176674843181968,936990907061504,4969309405367264,26354616443092800,139771093164846816,741272730213321216,3931322622695991104
%N A278681 Pisot sequence T(3,16).
%H A278681 <a href="/index/Ph#Pisot">Index entries for Pisot sequences</a>
%F A278681 a(n) = floor(a(n-1)^2/a(n-2)), a(0) = 3, a(1) = 16.
%F A278681 Conjectures: (Start)
%F A278681 G.f.: (3 - 2*x + x^2 - x^3)/(1 - 6*x + 4*x^2 - 2*x^3 + 2*x^4).
%F A278681 a(n) = 6*a(n-1) - 4*a(n-2) + 2*a(n-3) - 2*a(n-4). (End)
%t A278681 RecurrenceTable[{a[0] == 3, a[1] == 16, a[n] == Floor[a[n - 1]^2/a[n - 2]]}, a, {n, 25}]
%Y A278681 Cf. A008776 for definitions of Pisot sequences.
%Y A278681 Cf. A010920, A018920.
%K A278681 nonn,easy
%O A278681 0,1
%A A278681 _Ilya Gutkovskiy_, Nov 26 2016