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A161147
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Numbers which can be expressed as the product of numbers made of only nines.
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7
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9, 81, 99, 729, 891, 999, 6561, 8019, 8991, 9801, 9999, 59049, 72171, 80919, 88209, 89991, 98901, 99999, 531441, 649539, 728271, 793881, 809919, 890109, 899991, 970299, 989901, 998001, 999999, 4782969, 5845851, 6554439, 7144929, 7289271, 8010981, 8099919
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 81 = 9 * 9; 891 = 9 * 99; 8991 = 9 * 999.
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MATHEMATICA
| ns=Table[10^i-1, {i, 7}]; Take[Union[Join[ns, Flatten[Table[Times@@@Tuples[ns, x], {x, 2, 8}]]]], 50] [From Harvey P. Dale, Jan. 19, 2011]
nMax=10^7; ns=Table[10^i-1, {i, Floor[Log[10, nMax]]}]; u={1}; Do[While[u2=Union[u, Select[i*u, # <= nMax&]]; u != u2, u=u2], {i, ns}]; Rest[u]
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CROSSREFS
| Cf. A084034, A161140, A161141, A161142, A161143, A161144, A161145, A161146.
Sequence in context: A203656 A043087 A037414 * A175370 A158028 A043180
Adjacent sequences: A161144 A161145 A161146 * A161148 A161149 A161150
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KEYWORD
| nonn,base
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AUTHOR
| Claudio L Meller (claudiomeller(AT)gmail.com), Jun 03 2009
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EXTENSIONS
| More terms from Claudio L Meller (claudiomeller(AT)gmail.com), Jun 06 2009
Corrected and extended by Harvey P. Dale, Jan. 19, 2011
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