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A332475 Numbers k such that k and k + 1 have the same norm of the sum of unitary divisors in Gaussian integers (A332474). 1
5, 11, 37, 1738, 2772, 6600, 42251, 49913, 57816, 104754, 220324, 288350, 364452, 792156, 1711932, 1971475, 2607049, 2793473, 3211933, 3521148, 3526312, 4012736, 5805149, 5918276, 6522320, 6542147, 6635436, 7612267, 12604600, 14844791, 17078848, 19024332, 21177516 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
5 is a term since A332474(5) = A332474(6) = 80.
MATHEMATICA
f[p_, e_] := If[Abs[p] == 1, 1, (p^e + 1)]; normUsigma[n_] := Abs[Times @@ f @@@ FactorInteger[n, GaussianIntegers -> True]]^2; seq = {}; u1 = normUsigma[1]; Do[u2 = normUsigma[n]; If[u1 == u2, AppendTo[seq, n - 1]]; u1 = u2, {n, 2, 10^6}]; seq
CROSSREFS
Sequence in context: A074626 A090186 A205719 * A139515 A038708 A042719
KEYWORD
nonn
AUTHOR
Amiram Eldar, Feb 13 2020
STATUS
approved

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Last modified March 29 06:34 EDT 2024. Contains 371265 sequences. (Running on oeis4.)