cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

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Author

Amiram Eldar, Feb 15 2020

Keywords

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).

Examples

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

Crossrefs

Subsequence of A332531.

Programs

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