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Search: id:A091296
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| A091296 |
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Semiprimes with odd digits. |
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+0
5
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| 9, 15, 33, 35, 39, 51, 55, 57, 77, 91, 93, 95, 111, 115, 119, 133, 155, 159, 177, 319, 335, 339, 355, 371, 377, 391, 393, 395, 511, 515, 517, 519, 533, 535, 537, 551, 553, 559, 573, 579, 591, 597, 713, 717, 731, 737, 753, 755, 771, 779, 791, 793, 799, 913, 917
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Semiprimes with odd digits are more numerous than those with even digits, cf. A108636.
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MATHEMATICA
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Select[Range[1000], Plus@@Last/@FactorInteger[ # ]==2&&Union[OddQ/@IntegerDigits[ # ]]=={True}&]
PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[ Table[ #[[2]], {1}] & /@ FactorInteger[n]]; Select[ Range[ 938], PrimeFactorExponentsAdded[ # ] == 2 && Union[ OddQ /@ IntegerDigits[ # ]] == {True} &] (from Robert G. Wilson v)
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CROSSREFS
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Cf. A001358 (semiprimes), A108636.
Sequence in context: A051246 A062016 A108637 this_sequence A107076 A155775 A111148
Adjacent sequences: A091293 A091294 A091295 this_sequence A091297 A091298 A091299
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KEYWORD
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easy,nonn,base
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Feb 22 2004
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EXTENSIONS
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Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 25 2004
Edited by N. J. A. Sloane (njas(AT)research.att.com), Apr 20 2007
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