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A257751
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Quasi-Carmichael numbers to exactly one base.
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11
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35, 77, 143, 165, 187, 209, 231, 247, 273, 299, 357, 391, 399, 437, 493, 527, 561, 589, 598, 713, 715, 943, 989, 1015, 1073, 1189, 1247, 1295, 1333, 1537, 1547, 1705, 1729, 1739, 1829, 1886, 1927, 1961, 2015, 2021, 2257, 2279, 2387, 2397, 2419, 2451, 2479, 2501
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OFFSET
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1,1
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COMMENTS
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See A259238 for the corresponding bases.
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LINKS
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EXAMPLE
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a(1) = 35 because this is the first squarefree composite number n such that exactly one nonzero integer b exists such that for every prime factor p of n, p+b divides n+b (-3): 35=5*7 and 2, 4 both divide 32.
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PROG
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(PARI) for(n=2, 1000000, if(!isprime(n), if(issquarefree(n), f=factor(n); k=0; for(b=-(f[1, 1]-1), n, c=0; for(i=1, #f[, 1], if((n+b)%(f[i, 1]+b)>0, c++)); if(c==0, if(!b==0, k++))); if(k==1, print1(n, ", ")))))
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CROSSREFS
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Cf. A257750 (every number of bases).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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