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%I #15 Dec 22 2020 18:29:42
%S 2,4,11,24,41,117,278,527,1199,3116,6469,11753,33802,76443,136762,
%T 354144,873121,1721764,3565918,9653287,20783558,34867797,103232189,
%U 242017776,451910159,1064447283,2726446322,5583548873,10513816601,29729597084,66349305331
%N Values of y such that x^2 + y^2 = 5^n with x and y coprime and 0 < x < y.
%C The corresponding x-values are in A230710.
%H Zak Seidov, <a href="/A230711/b230711.txt">Table of n, a(n) for n = 1..200</a>
%H Chris Busenhart, Lorenz Halbeisen, Norbert Hungerbühler, Oliver Riesen, <a href="https://people.math.ethz.ch/~halorenz/publications/pdf/Miniatur.pdf">On primitive solutions of the Diophantine equation x^2+ y^2= M</a>, Eidgenössische Technische Hochschule (ETH Zürich, Switzerland, 2020).
%e a(4)=24 because 7^2+24^2=625=5^4.
%t Table[Select[PowersRepresentations[5^n, 2, 2], CoprimeQ[#[[1]], #[[2]]] &][[1,2]], {n, 33}] (* _T. D. Noe_, Nov 04 2013 *)
%Y Cf. A000351, A188949, A230623, A230645, A230710.
%K nonn
%O 1,1
%A _Colin Barker_, Oct 28 2013