[seqfan] Re: Primes formed by concatenating other primes.
Maximilian Hasler
maximilian.hasler at gmail.com
Tue Mar 2 19:25:32 CET 2010
The sequence
A141409
Prime numbers that cannot be formed by the concatenation of
previous terms.
2, 3, 5, 7, 11, 13, 17, 19, 29, 31, 41, 43, 47, 59, 61, 67, 71, 79,
83, 89, 97, 101, 103, 107, 109, 127, 131, 139, 149, 151, 157, 163,
167, 179, 181, 191, 199, 227, 239, 251, 257, 263, 269, 277, 281, 293,
307, 349, 401, 409, 419, 421, 431, 439, 443, 449, 457, 461
has bad terms, e.g. [227, 257, 277, 293, 307, ...]
are in A019549 and thus should not be here.
(for 227 the question might be if the definition should read "...of
TWO previous terms",
but this does not explain 293 which is clearly wrong (AFAICS)
- or must the terms remain "in order", additionally ?)
M.
On Tue, Mar 2, 2010 at 6:49 PM, Eric Angelini <Eric.Angelini at kntv.be> wrote:
>
> Hello SeqFans,
> could someone send me please a zipped file with
> 10000 terms? I'm looking for something funny!
> http://www.research.att.com/~njas/sequences/A019549
> Best,
> É.
>
>
>
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