A332531 Even numbers k such that A103230(k) is a perfect square.

442, 818, 1130, 1226, 1326, 1576, 2454, 3094, 3390, 3678, 3978, 4728, 4862, 5330, 5726, 5986, 6452, 7362, 7786, 7910, 8362, 8398, 8582, 8998, 9282, 10166, 10170, 10250, 11032, 11034, 11934, 12410, 12430, 13486, 13702, 14184, 14586, 15542, 15990, 17178, 17336

Offset: 1

Author

Amiram Eldar, Feb 15 2020

Keywords

• nonn

Comments

The odd numbers k such that A103230(k) is a perfect square are the numbers that are divisible only by primes congruent to 3 mod 4 (A004614).

Examples

			442 is a term since A103230(442) = 2433600 = 1560^2.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A004614, A006532, A103230.

Programs

Mathematica

Select[2 * Range[9000], IntegerQ @ Sqrt[Abs[DivisorSigma[1, #, GaussianIntegers -> True]]^2] &]