A337759 Squares that are the sum of 3 distinct nonzero squares.

49, 81, 121, 169, 196, 225, 289, 324, 361, 441, 484, 529, 625, 676, 729, 784, 841, 900, 961, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2401, 2500, 2601, 2704, 2809, 2916, 3025, 3136, 3249, 3364, 3481, 3600, 3721, 3844, 3969

Offset: 1

Author

Joseph Caliendo, Sep 18 2020

Keywords

• nonn

Comments

These are the squares in A004432. - Omar E. Pol, Sep 18 2020

Examples

			49 is a term because 6^2(36) + 3^2(9) + 2^2(4) = 7^2(49).
81 is a term because 8^2(64) + 4^2(16) + 1^2(1) = 9^2(81).
121 is a term because 9^2(81) + 6^2(36) + 2^2(4) = 11^2(121).
625 is a term because 9^2(81) + 12^2(144) + 20^2(400) = 25^2(625).
		

Crossrefs

Cf. A004432, A161992.

Programs

Mathematica

Select[Range[63]^2, Length @ Reduce[x^2 + y^2 + z^2 == # && 0 < x < y < z, {x, y, z}, Integers] > 0 &] (* Amiram Eldar, Sep 18 2020 *)

Formula

a(n) = A161992(n)^2. - Andrew Howroyd, Sep 18 2020