

A332478


Number that are unitary normmultiplyperfect numbers in Gaussian integers.


0




OFFSET

1,2


COMMENTS

Numbers k such that their norm of sum of unitary divisors in Gaussian integers, A332474(k), is divisible by their norm, k^2.
The corresponding ratios A332474(a(n))/(a(n)^2) are 1, 4, 1, 5, 5, 2, 5.


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

10 is a term since its sum of unitary divisors in Gaussian integers is 12 + 16*i, whose norm (12)^2 + 16^2 = 400 is divisible by 10^2 = 100.


MATHEMATICA

f[p_, e_] := If[Abs[p] == 1, 1, (p^e + 1)]; Select[Range[21000], Divisible[Abs[ Times @@ f @@@ FactorInteger[#, GaussianIntegers > True]]^2, #^2] &]


CROSSREFS

Cf. A002827, A327158, A332318, A332319, A332474.
Sequence in context: A255534 A262422 A248336 * A144814 A241174 A092887
Adjacent sequences: A332475 A332476 A332477 * A332479 A332480 A332481


KEYWORD

nonn,more


AUTHOR

Amiram Eldar, Feb 13 2020


STATUS

approved



