A103228 Real part of the sum of divisors function sigma(n) generalized for Gaussian integers.

1, 2, 4, -4, 4, 8, 8, -8, 13, -16, 12, -16, 6, 16, 16, 16, 6, 26, 20, -56, 32, 24, 24, -32, -36, -42, 40, -32, 8, -64, 32, 32, 48, -54, 32, -52, 8, 40, 24, 24, 10, 64, 44, -48, 52, 48, 48, 64, 57, -165, 24, -114, 10, 80, 48, -64, 80, -92, 60, -224, 12, 64, 104, -64, -120, 96, 68, -134, 96, -128, 72, -104, 12, -116, -144, -80, 96

Offset: 1

Author

T. D. Noe, Jan 26 2005

Keywords

• sign

Comments

See A103229 for the imaginary part and A103230 for the norm.

See A102506 for a complete description. Note that sigma(n) is real iff n is in A004614.

Links

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

Crossrefs

Cf. A004614, A102506, A103229, A103230.

Programs

Mathematica

Re[Table[DivisorSigma[1, n, GaussianIntegers -> True], {n, 100}]]