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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.

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

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%I A103228 #9 Feb 10 2020 06:14:05
%S A103228 1,2,4,-4,4,8,8,-8,13,-16,12,-16,6,16,16,16,6,26,20,-56,32,24,24,-32,
%T A103228 -36,-42,40,-32,8,-64,32,32,48,-54,32,-52,8,40,24,24,10,64,44,-48,52,
%U A103228 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
%N A103228 Real part of the sum of divisors function sigma(n) generalized for Gaussian integers.
%C A103228 See A103229 for the imaginary part and A103230 for the norm.
%C A103228 See A102506 for a complete description. Note that sigma(n) is real iff n is in A004614.
%H A103228 Amiram Eldar, <a href="/A103228/b103228.txt">Table of n, a(n) for n = 1..10000</a>
%t A103228 Re[Table[DivisorSigma[1, n, GaussianIntegers -> True], {n, 100}]]
%Y A103228 Cf. A004614, A102506, A103229, A103230.
%K A103228 sign
%O A103228 1,2
%A A103228 _T. D. Noe_, Jan 26 2005