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 A332317 Numbers k that are harmonic in Gaussian integers: k * A062327(k) is divisible by A103228(k) + i*A103229(k) (where i is the imaginary unit). 1
 1, 5, 130, 390, 585, 3250, 31980, 133250, 223860, 799500, 7195500, 13591500, 122323500, 258238500, 394153500, 405346500, 910630500, 1345558500, 2025133500, 8195674500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Analogous to harmonic numbers (A001599), with the number and sum of divisors functions generalized for Gaussian integers (A062327, A103228, A103229) instead of the number and sum of divisors functions (A000005, A000203). No more terms below 10^10. LINKS Table of n, a(n) for n=1..20. EXAMPLE 5 is a term since 5 * A062327(5)/(A103228(5) + i*A103229(5)) = 5 * 4 /(4 + 8*i) = 1 - 2*i is a Gaussian integer. MATHEMATICA Select[Range[10^4], Divisible[# * DivisorSigma[0, #, GaussianIntegers -> True], DivisorSigma[1, #, GaussianIntegers -> True]] &] CROSSREFS Cf. A000005, A000203, A001599, A062327, A103228, A103229, A103230. Sequence in context: A012083 A012226 A281818 * A069078 A003732 A203476 Adjacent sequences: A332314 A332315 A332316 * A332318 A332319 A332320 KEYWORD nonn,more AUTHOR Amiram Eldar, Feb 09 2020 STATUS approved

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Last modified December 7 18:28 EST 2023. Contains 367660 sequences. (Running on oeis4.)