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A034056
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Numbers with multiplicative digital root value 9.
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13
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9, 19, 33, 91, 119, 133, 191, 313, 331, 911, 1119, 1133, 1191, 1313, 1331, 1911, 3113, 3131, 3311, 9111, 11119, 11133, 11191, 11313, 11331, 11911, 13113, 13131, 13311, 19111, 31113, 31131, 31311, 33111, 91111, 111119, 111133, 111191, 111313, 111331
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OFFSET
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1,1
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COMMENTS
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Numbers with one 9 or two 3s, and zero or more 1s. - Daniel Forgues, Oct 09 2011
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LINKS
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Table of n, a(n) for n=1..40.
Eric Weisstein's World of Mathematics, Multiplicative Digital Root
Index entries for 10-automatic sequences.
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FORMULA
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There are n(n+1)(n+2)/6 elements up to 10^n, so a(n) is about 10^sqrt(6n).
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CROSSREFS
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Cf. A031347.
Cf. A034048, A002275, A034049, A034050, A034051, A034052, A034053, A034054, A034055, A034056 (numbers having multiplicative digital roots 0-9).
Sequence in context: A250663 A274590 A051811 * A195042 A198590 A297396
Adjacent sequences: A034053 A034054 A034055 * A034057 A034058 A034059
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KEYWORD
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nonn,base,easy
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AUTHOR
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Patrick De Geest, Sep 15 1998
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STATUS
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approved
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