A339956 Numbers that are the sum of an even square s and an odd square t such that 0 < s < t.

13, 29, 41, 53, 65, 85, 97, 117, 125, 137, 145, 157, 173, 185, 205, 221, 229, 233, 241, 261, 269, 289, 293, 305, 313, 325, 353, 365, 369, 377, 389, 397, 421, 425, 433, 445, 457, 461, 477, 485, 505, 533, 541, 545, 557, 565, 585, 593, 617, 629, 637, 641, 661, 673, 685, 689, 697

Offset

1,1

Links

Table of n, a(n) for n=1..57.

Example

29 is in the sequence since 2^2 + 5^2 = 29, 4 is even, 25 is odd, and 0 < 4 < 25.

Mathematica

Table[If[Sum[Mod[i + 1, 2] Mod[n - i, 2] (Floor[Sqrt[i]] - Floor[Sqrt[i - 1]]) (Floor[Sqrt[n - i]] - Floor[Sqrt[n - i - 1]]), {i, Floor[n/2]}] > 0, n, {}], {n, 700}] // Flatten

Crossrefs

Cf. A000404, A010052, A057653, A097269.

Sequence in context: A045472 A240950 A141293 * A352926 A339989 A120827

Adjacent sequences: A339953 A339954 A339955 * A339957 A339958 A339959

Keyword

nonn

Author

Wesley Ivan Hurt, Dec 24 2020

Status

approved