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A075000
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Smallest number such that n*a(n) is a concatenation of n consecutive integers; or 0 if no such number exists.
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13
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1, 6, 41, 864, 2469, 20576, 493827, 7098637639, 13717421, 1234567891, 82737383012865106529, 10288065758426, 3513762316247164732, 563643651522439401227280, 8230452606740808761
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OFFSET
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1,2
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COMMENTS
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Conjecture: For every n there exists a nonzero a(n).
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LINKS
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FORMULA
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EXAMPLE
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a(11) = 82737383012865106529 as 11*82737383012865106529 = 910111213141516171819 is the concatenation of 11 numbers from 9 to 19.
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MATHEMATICA
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f[ n_ ] := Block[ {id = Range@n}, While[ k = FromDigits@ Flatten@ IntegerDigits@ id/n; !IntegerQ@k, id++ ]; k ]; Array[ f, 16 ] (* Robert G. Wilson v, Oct 19 2007 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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