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A085155
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Powers of semiprimes.
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7
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1, 4, 6, 9, 10, 14, 15, 16, 21, 22, 25, 26, 33, 34, 35, 36, 38, 39, 46, 49, 51, 55, 57, 58, 62, 64, 65, 69, 74, 77, 81, 82, 85, 86, 87, 91, 93, 94, 95, 100, 106, 111, 115, 118, 119, 121, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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{1} UNION {A001358 semiprimes} UNION {A074985 squares of semiprimes} UNION {cubes of semiprimes} UNION {4th powers of semiprimes} UNION ... - Jonathan Vos Post, Sep 06 2006
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MATHEMATICA
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Select[Range@ 166, Function[n, Or[n == 1, And[Length@ # == 1, EvenQ@ First@ #], And[Length@ # == 2, SameQ @@ #]] &[FactorInteger[n][[All, -1]]]]] (* Michael De Vlieger, Mar 04 2017 *)
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PROG
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(PARI) is(n)=my(f=factor(n)[, 2]); #f==0 || (#f==2 && f[1]==f[2]) || (#f==1 && f[1]%2==0) \\ Charles R Greathouse IV, Oct 19 2015
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CROSSREFS
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Semiprime analog of A000961 = prime powers.
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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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