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A303356
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Unitary deficient-perfect numbers: unitary deficient numbers n such that 2*n-usigma(n) is a unitary divisor of n, where usigma is the sum of unitary divisors of n (A034448).
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1
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1, 2, 10, 12, 120, 4080, 5280, 6720, 17472, 137280, 174720, 908160, 29621760, 31100160, 41879040, 89806080, 99240960, 101391360, 143969280, 226652160, 466794240, 732103680, 760488960, 779412480, 916016640, 918382080, 951498240, 1001172480, 1365450240, 3151948800, 9464663040
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OFFSET
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1,2
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COMMENTS
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The unitary version of A271816.
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LINKS
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Table of n, a(n) for n=1..31.
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EXAMPLE
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120 is in the sequence since 2*120 - usigma(120) = 240 - 216 = 24, and 24 is a unitary divisor of 120.
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MATHEMATICA
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usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; aQ[n_] := Module[{d}, d=2n-usigma[n]; If[ d<=0, False, Divisible[n, d] && GCD[d, n/d] == 1 ]]; Select[Range[100000], aQ]
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CROSSREFS
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Cf. A034448, A271816, A303357.
Sequence in context: A055697 A055705 A156430 * A299317 A095914 A189079
Adjacent sequences: A303353 A303354 A303355 * A303357 A303358 A303359
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KEYWORD
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nonn
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AUTHOR
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Amiram Eldar, Apr 22 2018
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EXTENSIONS
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a(19)-a(31) from Giovanni Resta, Apr 26 2018
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STATUS
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approved
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