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Search: id:A141807
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| A141807 |
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If p^b(n,p) is the largest power of the prime p to divide n, then the positive integer n is included in the sequence if p(1)^b(n,p(1)) = p(2)^b(n,p(2))+1 = p(3)^b(n,p(3))+2 =...= p(k)^b(n,p(k))+k-1, where (p(1),p(2),p(3),...,p(k)) is some permutation of the distinct primes that divide n. |
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2
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 16, 17, 19, 20, 23, 25, 27, 29, 31, 32, 37, 41, 43, 47, 49, 53, 56, 60
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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All prime-powers are included in this sequence.
Sequence A141808 consists of terms of A141807 that are not prime powers.
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EXAMPLE
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The prime-factorization of 60 is 2^2 *3^1 *5^1. Since 5^1 = 2^2 +1 = 3^1 +2 (ie, the prime powers, in some order, occur in an arithmetic progression with a difference of 1 between consecutive terms), then 60 is included in the sequence.
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CROSSREFS
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Cf. A141808.
Sequence in context: A055201 A072303 A081061 this_sequence A072495 A126968 A126969
Adjacent sequences: A141804 A141805 A141806 this_sequence A141808 A141809 A141810
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KEYWORD
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more,nonn
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Jul 07 2008
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