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A346138
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Sphenic numbers that are the product of Mersenne primes.
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0
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651, 2667, 11811, 27559, 172011, 761763, 1777447, 2752491, 3120771, 7281799, 11010027, 12189603, 28442407, 32247967, 48758691, 49938051, 113770279, 116522119, 199753347, 466091143, 516026527, 2064117919, 3220807683, 7515217927, 12883304451, 30061043719, 33281679391, 45097156587, 133127479327
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OFFSET
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1,1
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COMMENTS
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The largest known sphenic number is a term of this sequence.
a(n) == 3 (mod 4) for n >= 1.
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LINKS
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EXAMPLE
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a(1) = 651, since 651 = 3*7*31.
a(2) = 2667, since 2667 = 3*7*127.
a(3) = 11811, since 11811 = 3*31*127.
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MATHEMATICA
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M = 2^MersennePrimeExponent[Range[12]] - 1; Take[ Union[ Times @@@ Subsets[ M, {3}]], 50]
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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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