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A115044
Middle term of smallest arithmetic prime triple with common difference 2n (or 0 if no such prime exists).
0
5, 7, 11, 11, 13, 17, 17, 0, 23, 23, 0, 29, 0, 31, 37, 0, 37, 43, 41, 43, 47, 0, 0, 53, 53, 0, 59, 0, 0, 67, 0, 67, 71, 71, 0, 79, 0, 0, 89, 83, 0, 89, 0, 0, 101, 0, 97, 101, 101, 0, 109, 107, 0, 131, 113, 0, 127, 0, 0, 131, 0, 127, 131, 0, 0, 137, 137, 0, 179, 0, 0, 149, 0, 0
OFFSET
1,1
COMMENTS
n's for which no prime exists: 8, 11, 13, 16, 22, 23, 26, 28, 29, 31, 35, 37, 38, 41, 43, 44, 46, 50, 53, 56, 58, 59, 61, 64, 65, 68, 70, 71, 73, 74, 76, 79, 80, 83, 85, 86, 88, 91, 92, 97, 98, 100, ...
MATHEMATICA
f[n_] := Block[{k = 2n + 1}, While[k < 10^5 && ! PrimeQ[k] || ! PrimeQ[k - 2n] || ! PrimeQ[k + 2n], k++ ]; If[k >= 10^5, 0, k]] (* Robert G. Wilson v *)
CROSSREFS
Cf. A098806.
Sequence in context: A317769 A104200 A249916 * A206770 A107257 A275515
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Feb 28 2006
EXTENSIONS
Corrected and extended by Robert G. Wilson v and Zak Seidov, Feb 28 2006
STATUS
approved