A333712 Numbers k that can be written as the sum of two nonzero squares whose difference divides k^2.

40, 45, 136, 160, 180, 325, 360, 369, 405, 544, 640, 720, 936, 1000, 1125, 1224, 1225, 1300, 1440, 1476, 1620, 1800, 1960, 2080, 2176, 2205, 2560, 2664, 2880, 2925, 3240, 3321, 3400, 3645, 3744, 3825, 4000, 4500, 4840, 4896, 4900, 5200, 5445, 5760, 5800, 5904

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Index entries for sequences related to sums of squares

Example

40 is in the sequence since 40 = 4 + 36 (both squares) and (36 - 4) = 32 | 40^2 = 1600.

Mathematica

Flatten[Table[If[Sum[(Floor[Sqrt[i]] - Floor[Sqrt[i - 1]]) (Floor[Sqrt[n - i]] - Floor[Sqrt[n - i - 1]]) (1 - Ceiling[n^2/(n - 2 i)] + Floor[n^2/(n - 2 i)]), {i, Floor[(n - 1)/2]}] > 0, n, {}], {n, 500}]]

Crossrefs

Cf. A004431.

Sequence in context: A346804 A364997 A046796 * A204746 A197734 A114839

Adjacent sequences: A333709 A333710 A333711 * A333713 A333714 A333715

Keyword

nonn

Author

Wesley Ivan Hurt, Apr 03 2020

Status

approved