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A126665
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a(n) = -n^2 + 9n + 53.
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5
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53, 61, 67, 71, 73, 73, 71, 67, 61, 53, 43, 31, 17, 1, -17, -37, -59, -83, -109, -137, -167, -199, -233, -269, -307, -347, -389, -433, -479, -527, -577, -629, -683, -739, -797, -857, -919, -983, -1049, -1117, -1187, -1259, -1333, -1409, -1487, -1567, -1649, -1733, -1819, -1907, -1997, -2089, -2183, -2279
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OFFSET
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0,1
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COMMENTS
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Quadratic equation derived from the four primes 61, 67, 71, 73 using the method of common differences. Many of the initial terms are primes.
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LINKS
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FORMULA
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G.f.: (53 - 98*x + 43*x^2)/(1 - x)^3. (End)
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EXAMPLE
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For n=8, -1*8^2 + 9*8 + 53 = 61.
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {53, 61, 67}, 60] (* Harvey P. Dale, Apr 04 2024 *)
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PROG
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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