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A237039
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Semiprimes of the form (2*p)^3 + 1, where p is prime.
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6
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65, 217, 10649, 195113, 1191017, 45882713, 55742969, 946966169, 2106997769, 2289529433, 2548895897, 10735357817, 26946035993, 54958685609, 77199941513, 131561576057, 132495001193, 440016501017, 456888832409, 623273556089, 848202406697, 966188398457
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OFFSET
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1,1
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LINKS
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Eric Weisstein's World of Mathematics, Semiprime.
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FORMULA
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EXAMPLE
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(2*2)^3 + 1 = 65 = 5*13 is a semiprime, so a(1) = 2.
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MATHEMATICA
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L = Select[Range[5000], PrimeQ[#] && PrimeQ[(2 #)^2 - 2 # + 1] && PrimeQ[2 # + 1] &]; (2 L)^3 + 1
Select[Table[(2p)^3+1, {p, Prime[Range[1000]]}], PrimeOmega[#]==2&] (* Harvey P. Dale, Jul 21 2021 *)
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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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