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A124983
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Nonprime numbers == 1 (mod 4) with a unique partition as a sum of 2 squares x^2 + y^2.
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4
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1, 9, 45, 49, 81, 117, 121, 153, 245, 261, 333, 361, 369, 405, 441, 477, 529, 549, 605, 637, 657, 729, 801, 833, 873, 909, 961, 981, 1017, 1053, 1089, 1233, 1341, 1377, 1413, 1421, 1557, 1573, 1629, 1737, 1773, 1805, 1813, 1849, 2009, 2057, 2061, 2097, 2169
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OFFSET
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1,2
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COMMENTS
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Intersection of A124982 and A125018. - Michel Marcus, Nov 02 2013
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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Select[4 * Range[0, 500] + 1, !PrimeQ[#] && Length @ PowersRepresentations[#, 2, 2] == 1 &] (* Amiram Eldar, Mar 12 2020 *)
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PROG
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(PARI) isok(n)= {if (isprime(n) || (n % 4 != 1), return (0)); A000161(n) == 1; } \\ Michel Marcus, Nov 02 2013
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CROSSREFS
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Cf. A000161, A002145, A124982, A125018, A125020.
Sequence in context: A096688 A181431 A249067 * A087969 A044111 A006886
Adjacent sequences: A124980 A124981 A124982 * A124984 A124985 A124986
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski, Nov 16 2006
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EXTENSIONS
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More terms from Michel Marcus, Nov 02 2013
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STATUS
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approved
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