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Search: id:A113623
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| A113623 |
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Highly composite numbers containing only noncomposite digits (1,2,3,5,7). |
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+0
2
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| 1, 2, 3, 5, 7, 12, 15, 21, 25, 27, 32, 35, 72, 75, 112, 125, 135, 175, 225, 252, 315, 375, 512, 525, 735, 1125, 1152, 1215, 1225, 1323, 1372, 1512, 1575, 1715, 2352, 3125, 3375, 13122, 13125, 15552, 25515, 25725, 31752, 35721, 55125, 77175, 111132
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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175 is a term since 175 = 5^2*7 and contains digits 1,5,7 none of which is composite. 175 is a member of A002473.
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MAPLE
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isA002473 := proc(n) local ifs ; if n <= 10 then true ; else ifs := ifactors(n)[2] ; if max( seq(op(1, i), i=ifs) ) <= 7 then true; else false ; fi ; fi ; end: isA113623 := proc(n) local digs ; if isA002473(n) then if convert(convert(n, base, 10), set) minus {1, 2, 3, 5, 7} <> {} then false ; else true ; fi ; else false ; fi ; end: for n from 1 to 150000 do if isA113623(n) then printf("%d, ", n) ; fi ; od; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 28 2007
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CROSSREFS
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Cf. A002473.
Sequence in context: A004683 A100036 A022438 this_sequence A078912 A105930 A122622
Adjacent sequences: A113620 A113621 A113622 this_sequence A113624 A113625 A113626
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 10 2005
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 28 2007
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