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Search: id:A145908
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| A145908 |
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Primes p such that p + floor(sqrt(p)) OR p + ceiling(sqrt(p)) is also prime. |
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2
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| 2, 3, 5, 13, 19, 31, 37, 41, 47, 53, 59, 71, 97, 103, 127, 137, 139, 151, 167, 179, 197, 241, 277, 293, 313, 331, 349, 389, 401, 419, 457, 487, 499, 547, 563, 569, 577, 593, 607, 617, 619, 647, 683, 701, 733, 769, 811, 829, 853, 857, 877, 881, 907, 911, 937
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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K. D. Balliet List of Primes Generated in p + floor(sqrt(p)) OR p + ceiling(sqrt(p))
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FORMULA
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A145907 UNION A086085. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 31 2008]
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EXAMPLE
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p = 3; 3 + ceiling(sqrt(3)) = 5, which is prime. p = 5; 5 + floor(sqrt(5)) = 7, which is prime.
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MAPLE
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for n from 1 to 820 do p := ithprime(n) ; f := p+floor(sqrt(p)) ; c := p+ceil(sqrt(p)) ; if isprime(f) or isprime(c) then printf("%d, ", p) ; fi; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 31 2008]
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CROSSREFS
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A145907, A086085
Sequence in context: A157976 A155738 A164958 this_sequence A061305 A142881 A163159
Adjacent sequences: A145905 A145906 A145907 this_sequence A145909 A145910 A145911
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KEYWORD
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nonn
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AUTHOR
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Kyle Balliet (kdballie(AT)bloomu.edu), Oct 24 2008, Nov 06 2008
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EXTENSIONS
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2 terms inserted and sequence extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 31 2008
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