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Search: id:A121326
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| A121326 |
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Primes of the form 4*n^2 + 1. |
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+0
9
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| 5, 17, 37, 101, 197, 257, 401, 577, 677, 1297, 1601, 2917, 3137, 4357, 5477, 7057, 8101, 8837, 12101, 13457, 14401, 15377, 15877, 16901, 17957, 21317, 22501, 24337, 25601, 28901, 30977, 32401, 33857, 41617, 42437, 44101, 50177, 52901, 55697
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Except for the initial 2 in A002496 this sequence is the same as A002496. Conjecture: The prime factors of all numbers of the form 4n^2+1 are also of the form 4m+1.
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EXAMPLE
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For n=4, 4n^2+1 = 17, prime.
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MATHEMATICA
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lst={}; Do[p=4*n^2+1; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 28 2009]
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PROGRAM
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(PARI) for(x=1, 200, y=4*x^2+1; if(isprime(y), print1(y", ")))
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CROSSREFS
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Cf. A002496.
Sequence in context: A145012 A147204 A168024 this_sequence A147219 A146280 A147181
Adjacent sequences: A121323 A121324 A121325 this_sequence A121327 A121328 A121329
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Aug 26 2006
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