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A094298
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Numbers m such that m and its 10's complement are both semiprimes, i.e., m and 10^k - m, where k is the number of digits of m, are semiprime.
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0
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4, 6, 14, 15, 26, 35, 38, 49, 51, 62, 65, 74, 85, 86, 91, 94, 111, 121, 122, 129, 134, 158, 159, 169, 183, 185, 187, 201, 206, 209, 215, 219, 221, 237, 247, 254, 287, 301, 302, 303, 305, 319, 321, 326, 329, 365, 371, 377, 386, 403, 411, 417, 427, 446, 447, 458
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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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201 is a term because both 201 and 1000 - 201 = 799 are semiprimes.
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MATHEMATICA
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Select[Range[500], PrimeOmega[#]==PrimeOmega[10^IntegerLength[#]-#]==2&] (* Harvey P. Dale, Jan 17 2013 *)
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CROSSREFS
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KEYWORD
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easy,nonn,base,changed
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AUTHOR
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STATUS
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approved
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