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 A201227 #28 Mar 04 2016 07:04:19
%S A201227 219375,4566375,82569375,1482276375,26598999375,477300306375,
%T A201227 8564807109375,153689228256375,2757841302099375,49487454210126375,
%U A201227 888016334480769375,15934806566444316375,285938501861517519375,5130958226940871626375,92071309583074172349375
%N A201227 a(n) = (A201225(n))^3 - (A201226(n))^2.
%C A201227 Values d of solutions (x,y,d) of x^3-y^2 = d with decreasing coefficient r=sqrt(x)/d which r tend to 1/(1350*sqrt(5)) when d tends to infinity.
%C A201227 Also infinity family of solutions Mordell curve with extension sqrt(5) (another than A200218).
%C A201227 Conjecture: No more infinite families of solutions Mordell curves with extension sqrt(5) than A201227 and A200218.
%C A201227 Ratio a(n+1)/a(n) tends to 9+4*sqrt(5) when n tends to infinity.
%C A201227 Because all values in this sequence are positive, it means that A201225, A201226 and A201227 are even indexes subset of another sequence.
%H A201227 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (19, -19, 1).
%F A201227 a(n) = (A201225(n))^3 - (A201226(n))^2.
%F A201227 a(n) = 19*a(n-1) - 19*a(n-2) + a(n-3).
%F A201227 G.f.: x*(3375*(-65-118*x+7*x^2))/((-1+x)*(1-18*x+x^2)).
%F A201227 a(n) = 3375*(-11-(-2+sqrt(5))*(9+4*sqrt(5))^(-n)+(2+sqrt(5))*(9+4*sqrt(5))^n). - _Colin Barker_, Mar 03 2016
%t A201227 LinearRecurrence[{19,-19,1},{219375,4566375,82569375},30] (* _Harvey P. Dale_, Sep 25 2012 *)
%K A201227 nonn
%O A201227 1,1
%A A201227 _Artur Jasinski_, Nov 28 2011