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Search: id:A124986
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| A124986 |
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Primes of the form 12k+5 generated recursively. Initial prime is 5. General term is a(n)=Min {p is prime; p divides 1+4Q^2; Mod[p,12]=5}, where Q is the product of previous terms in the sequence. |
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1
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| 5, 101, 1020101, 53, 29, 2507707213238852620996901, 449, 433361, 401, 925177698346131180901394980203075088053316845914981, 44876921, 17, 173
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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All prime divisors of 1+4Q^2 are congruent to 1 modulo 4.
At least one prime divisor of 1+4Q^2 is congruent to 2 modulo 3, and hence to 5 modulo 12.
The first seven terms are the same as those of A057207.
The next term is known but is too large to include.
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LINKS
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N. Hobson, Home page (listed in lieu of email address)
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EXAMPLE
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a(8) = 433361 is the smallest prime divisor congruent to 5 mod 12 of 1+4Q^2 =
3179238942812523869898723304484664524974766291591037769022962819805514576256901
= 13 * 433361 * 42408853 * 2272998442375593325550634821 *
5854291291251561948836681114631909089, where Q = 5 * 101 * 1020101 * 53 *
29 * 2507707213238852620996901 * 449.
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CROSSREFS
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Cf. A000945, A040117, A057204-A057208, A051308-A051335, A124984-A124993, A125037-A125045.
Adjacent sequences: A124983 A124984 A124985 this_sequence A124987 A124988 A124989
Sequence in context: A009765 A113073 A057207 this_sequence A123626 A052138 A007619
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KEYWORD
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nonn
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AUTHOR
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Nick Hobson, Nov 18 2006 and Nov 23 2006
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