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A097061
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Carmichael numbers C such that C-1 is not a Niven/Harshad number.
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2
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561, 63973, 75361, 162401, 278545, 656601, 825265, 838201, 852841, 1050985, 1857241, 1909001, 3224065, 3828001, 4903921, 5444489, 5481451, 5632705, 5968873, 6049681, 6189121, 7995169, 8355841, 8830801, 8927101, 9494101
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OFFSET
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1,1
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COMMENTS
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8355841, 8830801, 8927101 are the first three consecutive Carmichael numbers to fail the criterion.
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LINKS
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EXAMPLE
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Add all digits in 560 to get 11, which gives 560/11<>int(560/11) and continue likewise with 1104/6==int(1104/6), 1728/18==int(1728/18), etc.
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MATHEMATICA
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Select[Range[10^6], CompositeQ[#] && Divisible[# - 1, CarmichaelLambda[#]] && !Divisible[# - 1, Plus @@ IntegerDigits@(# - 1)] &] (* Amiram Eldar, Jun 24 2019 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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Rob Hoogers (chimera(AT)chimera.fol.nl), Jul 21 2004
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EXTENSIONS
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STATUS
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approved
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