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A174816
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Numbers n such that n^4 + n^2 - 1 is prime.
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1
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2, 3, 4, 8, 10, 12, 13, 14, 15, 19, 25, 26, 32, 33, 35, 37, 42, 43, 44, 45, 51, 53, 56, 57, 58, 62, 65, 68, 75, 77, 80, 84, 90, 91, 102, 103, 106, 108, 119, 122, 124, 139, 141, 143, 147, 152, 155, 164, 167, 168, 176, 177, 178, 196, 197, 198, 201, 202, 206, 208, 217, 222, 234, 235
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OFFSET
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1,1
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LINKS
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EXAMPLE
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for n=2, a(2) = 3 is in the sequence because 3^4 + 3^2 - 1 = 89 is prime.
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MATHEMATICA
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lst={}; Do[If[PrimeQ[n^4+n^2-1], AppendTo[lst, n]], {n, 400}]; lst
Select[Range[250], PrimeQ[#^4+#^2-1]&] (* Harvey P. Dale, Aug 24 2011 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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