OFFSET
1,2
COMMENTS
See A102506 for a complete description.
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
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Andrew Howroyd)
FORMULA
MATHEMATICA
Abs[Table[DivisorSigma[1, n, GaussianIntegers -> True], {n, 100}]]^2
PROG
(PARI) \\ See A102506 for formula.
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)))}
a(n)=norm(CSigma(n)); \\ Andrew Howroyd, Aug 03 2018
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
T. D. Noe, Jan 26 2005
STATUS
approved