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A087784
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Number of non-congruent solutions to x^2 + y^2 + z^2 = 1 mod n.
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1
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1, 4, 6, 24, 30, 24, 42, 96, 54, 120, 110, 144, 182, 168, 180, 384, 306, 216, 342, 720, 252, 440, 506, 576, 750, 728, 486, 1008, 870, 720, 930, 1536, 660, 1224, 1260, 1296, 1406, 1368, 1092, 2880, 1722, 1008, 1806, 2640, 1620, 2024, 2162, 2304, 2058, 3000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a(n) = n^2 * (3/2 if 4|n) * (Product_{primes p == 1 mod 4 dividing n} (1+1/p) * Product_{primes p == 3 mod 4 dividing n} (1-1/p). - Bjorn Poonen, Dec 09 2003.
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CROSSREFS
| Cf. A087687, A060968.
Sequence in context: A004032 A107952 A123046 * A174197 A071224 A164532
Adjacent sequences: A087781 A087782 A087783 * A087785 A087786 A087787
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KEYWORD
| mult,nonn
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AUTHOR
| Yuval Dekel (dekelyuval(AT)hotmail.com), Oct 06 2003
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EXTENSIONS
| More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jun 17 2005
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