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A175730
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Numbers with deficiency of 42.
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0
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43, 69, 99, 165, 1168, 1365, 2139136, 32062485, 33722368, 132701205, 8592621568
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OFFSET
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1,1
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COMMENTS
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Numbers with an abundance of -42.
7454198513685 is also in the sequence. - Alexander Violette, Jan 10 2021
Numbers of the form 2^k * (2^(k + 1) + 41) are in the sequence if and only if 2^(k + 1) + 41 is prime. - David A. Corneth, Jan 15 2021
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LINKS
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Table of n, a(n) for n=1..11.
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PROG
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(PARI) for(n=1, 100000000, if(((sigma(n)-2*n)==-42), print1(n, ", ")))
(PARI) is(n)=2*n-sigma(n)==42 \\ Charles R Greathouse IV, Jan 11 2021
(PARI) list(lim)=my(v=List()); forfactored(n=1, lim\1, if(2*n[1]-sigma(n)==42, listput(v, n[1]))); Vec(v) \\ Charles R Greathouse IV, Jan 11 2021
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CROSSREFS
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Cf. A033879 (deficiency).
Sequence in context: A139875 A174812 A146355 * A087765 A141971 A144974
Adjacent sequences: A175727 A175728 A175729 * A175731 A175732 A175733
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KEYWORD
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nonn,more,changed
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AUTHOR
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Jason G. Wurtzel, Aug 24 2010
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EXTENSIONS
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a(10) from Jon E. Schoenfield, Jan 13 2021
a(11) from Charles R Greathouse IV, Jan 15 2021
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STATUS
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approved
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