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 A236571 #9 Jan 30 2014 08:22:55
%S A236571 0,1,3,5,15,38,75,190,375,950,1875,4750,10296,23750,51480,118750,
%T A236571 257400,593750,1287000,2968750,6435000,14843750,34182196,74218750,
%U A236571 170910980,371093750,854554900,1855468750,4272774500,9277343750,21363872500,46386718750
%N A236571 Value of x for solution of 5^n = x^2 + y^2 with closest x and y (n >= 0, 0 <= x < y).
%C A236571 Corresponding values of y: 1,2,4,10,20,41,100,205,500,1025,2500,5125,11753,25625,58765 (A236572).
%t A236571 m = 30; Join[{0,1},Table[Reduce[{5^n == x^2+y^2,0 ≤ x ≤ y}, {x,y}, Integers][[-1,1,2]],{n,2,m}]]
%Y A236571 Cf. A121705, A236572.
%K A236571 nonn
%O A236571 0,3
%A A236571 _Zak Seidov_, Jan 29 2014