[seqfan] Re: A220952 "unkn" (author Don Knuth, Feb 20, 2013) - continuation?
jean-paul.allouche at imj-prg.fr
Fri Aug 25 16:21:16 CEST 2017
Dear Neil, dear all
It looks like any integer hae to be preceded by infinitely
many zeroes in its base-5 representation. So that the
condition is not empty for single digit numbers and
they all have (except 0) two adjacent fellows.
Le 25/08/17 à 16:06, Neil Sloane a écrit :
> I did some editing of the Knuth sequence A220952. But the essential
> thing is still missing, namely, how is the sequence defined?
> The first link will show you the statement of the problem, without you
> having to pay. But it is hard to follow.
> The second link is useless, unless you have access to JSTOR, it is
> basically an ad, an invitation for you to spend $19.00.
> I have the issue of the Monthly with the problem and solution and
> could send a copy to anyone who wants to help.
> I'm confused by one point: the problem says each positive integer is
> adjacent to exactly two positive integers. But 1, 2, 3, and 4 are all
> mutually adjacent (since the condition is vacuous for single-digit
> numbers), so 1 is adjacent to three numbers, 2, 3, and 4.
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