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Search: id:A085645
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| A085645 |
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Smallest number having n divisors ending with 1 or 9. |
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+0
1
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| 1, 9, 63, 99, 441, 693, 5103, 1881, 5733, 4851, 35721, 9009
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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A. Stenger, An Excess of Divisors
Wikipedia, Table of divisors
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EXAMPLE
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The divisors of 63 are 1, 3, 7, 9, 21, and 63. Three of them end either in 1 or 9. No smaller number satisfies this condition, so a(3) = 63
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MATHEMATICA
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tbl=Table[Length[Select[IntegerDigits/@Divisors[i], Last[ # ]==1||Last[ # ]==9&]], {i, 50000}]; Table[First[Position[tbl, i]], {i, 12}]//Flatten
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CROSSREFS
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Sequence in context: A027234 A081574 A084151 this_sequence A015669 A073378 A022733
Adjacent sequences: A085642 A085643 A085644 this_sequence A085646 A085647 A085648
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KEYWORD
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nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), Jul 11 2003
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EXTENSIONS
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Corrected and extended by Harvey P. Dale (hpd1(AT)nyu.edu), Jul 18 2003
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