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A337759
Squares that are the sum of 3 distinct nonzero squares.
0
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
1,1
COMMENTS
These are the squares in A004432. - Omar E. Pol, Sep 18 2020
FORMULA
a(n) = A161992(n)^2. - Andrew Howroyd, Sep 18 2020
EXAMPLE
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).
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 *)
CROSSREFS
Sequence in context: A294028 A056938 A267986 * A207638 A286095 A106311
KEYWORD
nonn
AUTHOR
Joseph Caliendo, Sep 18 2020
STATUS
approved