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A131694
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Numbers n such that S(n) = prime, where S(n) = S(n-1) + A000040(n)*(-1)^n; S(0)=0.
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1
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1, 4, 6, 8, 10, 12, 18, 28, 32, 38, 42, 46, 50, 52, 54, 64, 68, 70, 72, 74, 76, 86, 88, 98, 100, 110, 126, 128, 130, 140, 146, 152, 162, 192, 202, 214, 226, 242, 252, 258, 264, 270, 290, 294, 304, 308, 314, 316, 320, 322, 332, 342, 348, 352, 358, 360
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OFFSET
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1,2
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COMMENTS
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The sequence include as first term the only case where S(n) = -1 times a prime: S(1)=-2.
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LINKS
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EXAMPLE
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S(3)=((0+2*-1)+3*1)+5*-1 = -4, S(4)= -4 + 7*1 = 3 is prime, hence 4 is a term.
S(5)=((((0+2*-1)+3*1)+5*-1)+7*1)+11*-1 = -8, S(6)= -8 + 13*1 = 5 is prime, hence 6 is a term.
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MATHEMATICA
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S=0; Do[S=S+Prime[n]*(-1)^n; If[PrimeQ[S]==True, Print[n]], {n, 1, 10^3, 1}]
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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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