A339956 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

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

(list; graph; refs; listen; history; text; internal format)

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