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A085718
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Numbers n such that sopfr(n)/spf(n) is a semiprime and sopfr(n)/lpf(n) is a semiprime, where sopfr(n) = A001414(n) is sum of primes dividing n (with repetition), spf(n) and lpf(n) are smallest and largest primes dividing n, respectively. Also, spf(n)!=lpf(n).
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0
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72, 576, 648, 750, 800, 900, 960, 1080, 3430, 4116, 4900, 5880, 6272, 7000, 7056, 7938, 8400, 8960, 9450, 10080, 10752, 11340, 12096, 13608, 18750, 20000, 22500, 24000, 25600, 27000, 28800, 30375, 30720, 32400, 34560, 36450, 36864, 37268
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OFFSET
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1,1
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LINKS
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EXAMPLE
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648=2^3*3^4 is a term because 2+2+2+3+3+3+3 = 18 and 18/2 = 9 and 18/3 = 6.
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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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