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 A124985 Primes of the form 8k+7 generated recursively. Initial prime is 7. General term is min{p is prime; p divides 8Q^2-1; p == 7 (mod 8)}, where Q is the product of the previous terms. 0
 7, 23, 207367, 1902391, 167, 1511, 28031, 79, 3142977463, 2473230126937097422987916357409859838765327, 2499581669222318172005765848188928913768594409919797075052820591, 223 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 8Q^2-1 always has a prime divisor congruent to 7 modulo 8. REFERENCES D. M. Burton, Elementary Number Theory, McGraw-Hill, Sixth Edition (2007), p. 182. LINKS N. Hobson, Home page (listed in lieu of email address) EXAMPLE a(4) = 1902391 is the smallest prime divisor, congruent to 7 modulo 8, of 8Q^2-1 = 8917046441372551 = 97 * 1902391 * 48322513, where Q = 7 * 23 * 207367. CROSSREFS Cf. A000945, A007522, A057204-A057208, A051308-A051335, A124984-A124993, A125037-A125045. Sequence in context: A009047 A129662 A012482 * A126612 A196113 A070410 Adjacent sequences:  A124982 A124983 A124984 * A124986 A124987 A124988 KEYWORD nonn AUTHOR Nick Hobson Nov 18 2006 EXTENSIONS Edited and added a(11)-a(12) by Max Alekseyev, May 31 2013 STATUS approved

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