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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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1
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 8355841, 8830801, 8927101 are the first three consecutive Carmichael numbers to fail the criterion.
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REFERENCES
| Granville, Andrew and Pomerance, Carl, Two contradictory conjectures concerning Carmichael numbers. Math. Comp. 71 (2002), no. 238, 883-908.
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LINKS
| Granville, Andrew and Pomerance, Carl, Two contradictory conjectures concerning Carmichael numbers
Rob Hoogers, Complete list of terms UP to 10^16 with all relevant data (5.3MB zipped textfile)
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FORMULA
| a(n) = if(sum of digits(n-1))/number of digits<>int(sum of digits(n-1)/number of digits, n, 0)
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EXAMPLE
| 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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PROG
| (pseudocode) if((n-1)/digitsum(n-1)<>int(n-1)/digitsum(n-1), n, 0)
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CROSSREFS
| Cf. A002997.
Sequence in context: A141706 A083736 A006931 * A139089 A202562 A121508
Adjacent sequences: A097058 A097059 A097060 * A097062 A097063 A097064
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KEYWORD
| nonn,base
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AUTHOR
| Rob Hoogers (chimera(AT)chimera.fol.nl), Jul 21 2004
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EXTENSIONS
| Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 16 2006
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