This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A161147 Numbers which can be expressed as the product of numbers made of only nines. 7
 1, 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; text; internal format)
 OFFSET 1,2 COMMENTS 81 = 9 * 9; 891 = 9 * 99; 8991 = 9 * 999. LINKS MATHEMATICA ns=Table[10^i-1, {i, 7}]; Take[Union[Join[ns, Flatten[Table[Times@@@Tuples[ns, x], {x, 2, 8}]]]], 50]  (* 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] CROSSREFS Cf. A084034, A161140, A161141, A161142, A161143, A161144, A161145, A161146. Sequence in context: A203656 A043087 A037414 * A209220 A207689 A209225 Adjacent sequences:  A161144 A161145 A161146 * A161148 A161149 A161150 KEYWORD nonn,base AUTHOR Claudio Meller, Jun 03 2009 EXTENSIONS More terms from Claudio Meller, Jun 06 2009 Corrected and extended by Harvey P. Dale, Jan 19 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 25 22:14 EDT 2019. Contains 324357 sequences. (Running on oeis4.)