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A072569
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Odd interprimes.
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24
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9, 15, 21, 39, 45, 69, 81, 93, 99, 105, 111, 129, 165, 195, 205, 217, 225, 231, 279, 309, 315, 351, 363, 381, 393, 399, 405, 441, 453, 459, 465, 473, 483, 489, 495, 501, 515, 615, 625, 645, 667, 675, 687, 705, 723, 741, 747, 759, 765, 771, 803, 825, 855, 861
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OFFSET
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1,1
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COMMENTS
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The interprimes (A024675) are those integers that lie at the midpoint between consecutive odd primes.
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LINKS
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MATHEMATICA
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a = Table[ Prime[n], {n, 2, 200}]; b = {}; Do[d = (a[[n + 1]] - a[[n]])/2; If[ OddQ[ a[[n]] + d], b = Append[b, a[[n]] + d]], {n, 1, 198}]; b
Select[Plus @@@ Partition[Table[Prime[n], {n, 2, 100}], 2, 1]/2, OddQ]
Select[Mean/@Partition[Prime[Range[2, 200]], 2, 1], OddQ] (* Harvey P. Dale, Jan 22 2019 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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