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Search: id:A138389
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| A138389 |
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Binomial primes: positive integers n such that every i not exceeding n/2 for which (n,i)>1 does not divide binomial(n-i-1,i-1). |
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2
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19, 20, 21, 23, 24, 25, 29, 31, 33, 35, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 143, 149, 151, 157, 163, 167, 169, 173
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OFFSET
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1,2
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COMMENT
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Every i not exceeding n/2 for which (n,i)=1 divides binomial(n-i-1,i-1). For n>24,a(n) is either prime or square of a prime or a product of twin primes.
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REFERENCES
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V. Shevelev, On divisibility of binomial(n-i-1,i-1) by i, International J. of Number Theory, 3,no.1(2007),119-139.
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CROSSREFS
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Cf. A000040, A001248, A077800, A037074.
Sequence in context: A127034 A095392 A140401 this_sequence A032963 A033065 A017906
Adjacent sequences: A138386 A138387 A138388 this_sequence A138390 A138391 A138392
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KEYWORD
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nonn
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AUTHOR
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Vladimir Shevelev (shevelev(AT)bgu.ac.il), May 08 2008
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