[seqfan] A032734
Harvey P. Dale
hpd1 at nyu.edu
Sat Oct 22 19:46:29 CEST 2011
I am confused about this sequence. It states that it comprises
numbers that "cannot be prefixed or followed by any digit to form a
prime." One of its terms, e.g., is 25213, but 252139 is a prime. Is
the definition wrong, or unclear, or is it simply that the term is
wrong? If I treat the "or" in the definition as exclusive, so that
prepending digits is one test and appending digits is a separate test, I
generate lots of terms that aren't in the sequence.
Harvey
-----Original Message-----
From: seqfan-bounces at list.seqfan.eu
[mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Maximilian Hasler
Sent: Saturday, October 22, 2011 1:09 PM
To: Sequence Fanatics Discussion list
Subject: [seqfan] Re: Strange comment in A003418
The contributor did not specify for which n this has to hold.
Obviously the inequality cannot hold for n=1, since the rhs is 0 and
the lhs nonnegative.
Maximilian
On Sat, Oct 22, 2011 at 6:31 AM, Georgi Guninski <guninski at guninski.com>
wrote:
> A003418 a(0) = 1; for n >= 1, a(n) = least common multiple (or lcm) of
{1, 2, ..., n}
>
> An assertion equivalent to the Riemann hypothesis is: | log(a(n)) - n
| < sqrt(n) * log(n)^2. - Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 27
2006
>
> According to my computations the inequality fails for n in {1,2}.
>
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