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 A332473 #10 Feb 14 2020 03:21:56 %S A332473 0,2,0,0,8,8,0,-8,0,16,0,0,18,16,32,0,22,20,0,-24,0,24,0,-32,8,30,0,0, %T A332473 36,64,0,32,0,34,64,0,44,40,72,-24,50,64,0,0,80,48,0,0,0,-40,88,-54, %U A332473 62,56,96,-64,0,52,0,-96,72,64,0,0,120,96,0,-66,0,128,0 %N A332473 The imaginary part of the sum of unitary divisors function (usigma) generalized for Gaussian integers. %C A332473 See A332472 for a description. %H A332473 Amiram Eldar, <a href="/A332473/b332473.txt">Table of n, a(n) for n = 1..10000</a> %e A332473 a(4) = 0 since 4 = -(1 + i)^4 in Gaussian integers (i is the imaginary unit), so usigma(4) = (1 + i)^4 + 1 = -3, and a(4) = Im(-3) = 0. %t A332473 f[p_, e_] := If[Abs[p] == 1, 1, (p^e + 1)]; usigma[n_] := Times @@ f @@@ FactorInteger[n, GaussianIntegers -> True]; a[n_] := Im[usigma[n]]; Array[a, 100] %Y A332473 Cf. A034448, A103229, A332472 (the real part), A332474 (the norm). %K A332473 sign %O A332473 1,2 %A A332473 _Amiram Eldar_, Feb 13 2020