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Search: id:A050480
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| A050480 |
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Numbers that can be written as a concatenation of distinct proper divisors. |
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+0
1
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| 12, 15, 24, 36, 48, 110, 120, 124, 125, 126, 128, 132, 135, 150, 162, 168, 175, 184, 210, 216, 220, 240, 248, 250, 264, 312, 315, 324, 330, 360, 375, 384, 396, 412, 416, 420, 432, 440, 480, 510, 520, 525, 550, 612, 624, 630, 648, 660, 672, 714, 728, 735
(list; graph; listen)
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OFFSET
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0,1
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EXAMPLE
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714 is divisible by 7 and 14
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MATHEMATICA
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f[ x_, y_ ] := (y==Take[ x, Min[ Length[ y ], Length[ x ] ] ]) g[ {}, _ ] := True; g[ LL_, DD_ ] := Module[ {}, a=Select[ DD, f[ LL, IntegerDigits[ # ] ]& ]; Apply[ Or, Map[ g[ Drop[ LL, Length[ IntegerDigits[ # ] ] ], Complement[ DD, {#} ] ]&, a ] ] ] h[ n_ ] := h[ n ]=g[ IntegerDigits[ n ], Drop[ Divisors[ n ], -1 ] ] Select[ Range[ 2000 ], h ]
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CROSSREFS
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Adjacent sequences: A050477 A050478 A050479 this_sequence A050481 A050482 A050483
Sequence in context: A117815 A050696 A122040 this_sequence A063604 A015904 A124521
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KEYWORD
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base,easy,nice,nonn
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AUTHOR
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Erich Friedman (efriedma(AT)stetson.edu), Dec 24 1999
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