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A332478
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Number that are unitary norm-multiply-perfect numbers in Gaussian integers.
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0
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OFFSET
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1,2
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COMMENTS
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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.
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LINKS
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Table of n, a(n) for n=1..7.
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EXAMPLE
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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.
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MATHEMATICA
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f[p_, e_] := If[Abs[p] == 1, 1, (p^e + 1)]; Select[Range[21000], Divisible[Abs[ Times @@ f @@@ FactorInteger[#, GaussianIntegers -> True]]^2, #^2] &]
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CROSSREFS
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Cf. A002827, A327158, A332318, A332319, A332474.
Sequence in context: A255534 A262422 A248336 * A144814 A241174 A092887
Adjacent sequences: A332475 A332476 A332477 * A332479 A332480 A332481
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KEYWORD
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nonn,more
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AUTHOR
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Amiram Eldar, Feb 13 2020
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STATUS
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approved
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