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A109255
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a(n) = (p^2 - 1) / 12, where p is the n-th prime of the form 4*k+1.
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1
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2, 14, 24, 70, 114, 140, 234, 310, 444, 660, 784, 850, 990, 1064, 1564, 1850, 2054, 2494, 2730, 3104, 3234, 4370, 4524, 4840, 5504, 6030, 6394, 6580, 7154, 8164, 8374, 9464, 10150, 10384, 11594, 12610, 13134, 13400, 13940, 14770, 15624, 16800, 17404
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OFFSET
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1,1
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REFERENCES
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G. Pólya and G. Szegő, Problems and Theorems in Analysis II (Springer 1924, reprinted 1972), Part Eight, Chap. 1, Sect. 2, Problem 20.
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LINKS
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FORMULA
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a(n) = Sum_{k=1..(p-1)/4} floor(sqrt(k*p)), where p = primes of the form 4*n+1.
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MATHEMATICA
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Map[(#^2 - 1)/12 &, Select[4 Range[120] + 1, PrimeQ]] (* Michael De Vlieger, Dec 27 2019 *)
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PROG
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(Magma) [(p^2 - 1) / 12: p in PrimesUpTo(500)| p mod 4 eq 1]; // Marius A. Burtea, Dec 29 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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