A085989 Numbers that can be expressed as a sum of two squares, each >=2.

8, 13, 18, 20, 25, 29, 32, 34, 40, 41, 45, 50, 52, 53, 58, 61, 65, 68, 72, 73, 74, 80, 85, 89, 90, 97, 98, 100, 104, 106, 109, 113, 116, 117, 125, 128, 130, 136, 137, 145, 146, 148, 149, 153, 157, 160, 162, 164, 169, 170, 173, 178, 180, 181, 185, 193, 194, 200

Offset: 1

Author

Eric W. Weisstein, Jul 06 2003

Keywords

• nonn

Examples

			8 = 2^2 + 2^2, 13 = 2^2 + 3^2, ...
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Landau-Ramanujan Constant

Crossrefs

Cf. A001481.

Programs

Maple

filter:= n -> ormap(t -> subs(t,x)>1 and subs(t,y) > 1, [isolve(x^2 + y^2 = n)]):
select(filter, [$0..200]); # Robert Israel, Mar 06 2017

Mathematica

r[n_] := Reduce[2 <= x <= y && n == x^2 + y^2, {x, y}, Integers]; Select[Range[200], r[#] =!= False &] (* Jean-François Alcover, Oct 29 2012 *)

Extensions

Offset changed by Robert Israel, Mar 06 2017