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A108656
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Least a(n)>0 such that a(n-2)*n^2+a(n-1)*n+a(n) is a prime.
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2
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2, 3, 2, 3, 2, 7, 2, 3, 2, 11, 4, 5, 2, 1, 2, 5, 10, 1, 2, 3, 2, 3, 2, 1, 2, 5, 4, 17, 6, 13, 4, 1, 2, 5, 8, 11, 10, 3, 2, 9, 2, 11, 6, 3, 4, 15, 6, 1, 6, 1, 4, 5, 2, 11, 4, 1, 10, 3, 36, 7, 16, 1, 10, 15, 12, 5, 14, 5, 4, 1, 14, 5, 40, 1, 2, 11, 8, 11, 24, 17, 2, 1, 12, 5, 8, 23, 10, 29, 8, 1, 4, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Corresponding primes in A108657.
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EXAMPLE
| a(1)=2, a(2)=3 and a(3)=2 because 2*3^2+3*3+2=29 is aprime; a(4)=3, a(5)=2 and a(6)=7 because 3*6^2+2*6+7=127 is a prime.
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MATHEMATICA
| a=2; b=3; s={a, b}; Do[c=Prime[PrimePi[a*n^2+b*n]+1]-a*n^2-b*n; AppendTo[s, c]; a=b; b=c, {n, 3, 200}]; A108656=s
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CROSSREFS
| Cf. A108657.
Sequence in context: A087317 A086489 A015886 * A164962 A119880 A075019
Adjacent sequences: A108653 A108654 A108655 * A108657 A108658 A108659
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KEYWORD
| nonn
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AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Jun 14 2005
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