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A072753
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Maximum gap in two-stage prime-sieves.
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1
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OFFSET
| 3,1
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FORMULA
| Let p(n) be the sequence of primes, i.e. p(1)=2. For n>=3 we define a(n) = max { m IN N | EXIST c(k), d(k) IN N, k=3, .., n : FOR ALL i IN {1, .., m} EXISTS j IN {3, .., n} : i == c(j) (mod p(j)) OR i == d(j) (mod p(j)) }
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EXAMPLE
| a(5) = 10 because c(3)=2, d(3)=4, c(4)=1, d(4)=3, c(5)=4, d(5)=6 satisfy the requirements: 1 == 1 (mod 7), 2 == 2 (mod 5), 3 == 3 (mod 7), 4 == 4 (mod 5), 5 == 5 (mod 11), 6 == 6 (mod 11), 7 == 2 (mod 5), 8 == 1 (mod 7), 9 == 4 (mod 5), 10 == 3 (mod 7)
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CROSSREFS
| Cf. A072752.
Sequence in context: A156806 A192523 A065832 * A009884 A032023 A094837
Adjacent sequences: A072750 A072751 A072752 * A072754 A072755 A072756
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KEYWORD
| hard,more,nonn
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AUTHOR
| Mario Ziller (datalab(AT)gmx.de), Jul 10 2002
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EXTENSIONS
| One more term from Mario Ziller (datalab(AT)gmx.de), May 30 2005
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