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A234102
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Integers of the form (p*q*r + 1)/2, where p, q, r are distinct primes.
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6
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53, 83, 98, 116, 128, 137, 143, 173, 179, 193, 200, 215, 218, 228, 233, 242, 278, 281, 298, 305, 308, 314, 323, 326, 332, 333, 353, 358, 371, 380, 389, 398, 403, 431, 443, 449, 452, 458, 468, 479, 485, 494, 501, 503, 508, 512, 523, 533, 543, 548, 553, 557
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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53 = (3*5*7 + 1)/2.
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MATHEMATICA
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t = Select[Range[1, 10000, 2], Map[Last, FactorInteger[#]] == Table[1, {3}] &]; Take[(t + 1)/2, 120] (* A234102 *)
v = Flatten[Position[PrimeQ[(t + 1)/2], True]] ; w = Table[t[[v[[n]]]], {n, 1, Length[v]}] (* A234103 *)
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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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