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.
%I A103230 #16 Feb 10 2020 06:14:35
%S A103230 1,13,16,41,80,208,64,113,169,1040,144,656,360,832,1280,481,520,2197,
%T A103230 400,3280,1024,1872,576,1808,2257,4680,1600,2624,1360,16640,1024,2113,
%U A103230 2304,6760,5120,6929,2000,5200,5760,9040,2600,13312,1936,5904,13520
%N A103230 Norm of the sum of divisors function sigma(n) generalized for Gaussian integers.
%C A103230 See A102506 for a complete description.
%C A103230 See A103228 and A103229 for the real and imaginary parts.
%C A103230 Multiplicative because the sigma function on Gaussian integers as defined in A102506 is multiplicative and the norm is completely multiplicative. - _Andrew Howroyd_, Aug 03 2018
%H A103230 Amiram Eldar, <a href="/A103230/b103230.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Andrew Howroyd)
%F A103230 a(n) = A103228(n)^2 + A103229(n)^2. - _Andrew Howroyd_, Aug 03 2018
%t A103230 Abs[Table[DivisorSigma[1, n, GaussianIntegers -> True], {n, 100}]]^2
%o A103230 (PARI) \\ See A102506 for formula.
%o A103230 CSigma(z)={my(f=factor(z,I)); prod(i=1, #f~, my([p,e]=f[i,]); if(norm(p)==1, 1, (p^(e+1)-1)/(p-1)))}
%o A103230 a(n)=norm(CSigma(n)); \\ _Andrew Howroyd_, Aug 03 2018
%Y A103230 Cf. A102506, A102574, A103224, A103228, A103229.
%K A103230 nonn,mult
%O A103230 1,2
%A A103230 _T. D. Noe_, Jan 26 2005