A332532 Even numbers k such that the sum of divisors of k in Gaussian integers is a real number.

10250, 30750, 40400, 71750, 92250, 112750, 121200, 194750, 215250, 235750, 276750, 282800, 308050, 317750, 338250, 363600, 440750, 444400, 467860, 481750, 502250, 584250, 604750, 645750, 686750, 707250, 727750, 767600, 789250, 809750, 830250, 848400, 850750

Offset

1,1

Comments

Even numbers k such that A103229(k) = 0.

The odd numbers with this property are the numbers that are divisible only by primes congruent to 3 mod 4 (A004614).

Links

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

Example

10250 is a term since its sum of divisors in Gaussian integers is 41600 which is a real number.

Mathematica

Select[Range[2, 10^6, 2], Im[DivisorSigma[1, #, GaussianIntegers -> True]] == 0 &]

Crossrefs

Subsequence of A332531.

Cf. A004614, A103228, A103229.

Sequence in context: A109176 A187796 A157735 * A252031 A356979 A187311

Adjacent sequences: A332529 A332530 A332531 * A332533 A332534 A332535

Keyword

nonn

Author

Amiram Eldar, Feb 15 2020

Status

approved