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Search: id:A139538
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| A139538 |
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Odd numbers of the form x^2+5y^2 not divisable by 5. |
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+0
1
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| 9, 21, 29, 41, 49, 61, 69, 81, 89, 101, 109, 129, 141, 149, 161, 181, 189, 201, 229, 241, 249, 261, 269, 281, 301, 309, 321, 329, 349, 369, 381, 389, 401, 409, 421, 441, 449, 461, 469, 489, 501, 509, 521, 529, 541, 549, 569, 581, 601, 609, 621, 641, 661, 669
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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All numbers in this sequence are divisable by primes A139513
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REFERENCES
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Dirichlet & Dedekins Lectures on Number Theory (English Translation 1999) p. 119.
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MATHEMATICA
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a = {}; Do[Do[k = x^2 + 5 y^2; If[OddQ[k], If[Mod[k, 5] != 0, AppendTo[a, k]]], {x, 1, 100}], {y, 1, 100}]; Union[a] (*Artur Jasinski*)
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CROSSREFS
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Adjacent sequences: A139535 A139536 A139537 this_sequence A139539 A139540 A139541
Sequence in context: A036316 A039289 A045252 this_sequence A110701 A133929 A086470
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Apr 25 2008, Apr 28 2008
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