[seqfan] Re: A069570; Numbers in which the n-th digit is either a divisor or a multiple of n.
israel at math.ubc.ca
israel at math.ubc.ca
Tue Sep 27 17:21:54 CEST 2016
On Sep 27 2016, David Corneth wrote:
>What's this sequence supposed to be? a(21) = 23 but 23 has no 21-th digit.
>
>--
>Seqfan Mailing list - http://list.seqfan.eu/
>
In each member of the sequence, each digit is a divisor or multiple of its
index in the number (counted from right to left). Thus 23 is a term because
3 is a divisor or multiple 1 and 2 is a divisor or multiple of 2. 123, 323,
623 and 923 are terms, but 223 is not.
Cheers
Robert
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