A230711 Values of y such that x^2 + y^2 = 5^n with x and y coprime and 0 < x < y.

2, 4, 11, 24, 41, 117, 278, 527, 1199, 3116, 6469, 11753, 33802, 76443, 136762, 354144, 873121, 1721764, 3565918, 9653287, 20783558, 34867797, 103232189, 242017776, 451910159, 1064447283, 2726446322, 5583548873, 10513816601, 29729597084, 66349305331

Offset: 1

Author

Colin Barker, Oct 28 2013

Keywords

• nonn

Comments

The corresponding x-values are in A230710.

Examples

			a(4)=24 because 7^2+24^2=625=5^4.
		

Links

• Zak Seidov, Table of n, a(n) for n = 1..200
• Chris Busenhart, Lorenz Halbeisen, Norbert Hungerbühler, Oliver Riesen, On primitive solutions of the Diophantine equation x^2+ y^2= M, Eidgenössische Technische Hochschule (ETH Zürich, Switzerland, 2020).

Crossrefs

Cf. A000351, A188949, A230623, A230645, A230710.

Programs

Mathematica

Table[Select[PowersRepresentations[5^n, 2, 2], CoprimeQ[#[[1]], #[[2]]] &][[1,2]], {n, 33}] (* T. D. Noe, Nov 04 2013 *)