Where are the primes!? [seqfan]
Eric W. Weisstein
eww6n at carina.astro.virginia.edu
Fri May 8 00:52:12 CEST 1998
Sloane's sequences A007908 (1, 12, 123, 1234, ...,) and A000422 (1, 21,
321, 4321, ...) contain surprisingly few primes. Ralf Stephan
(http://www.tmt.de/~stephan/sm.ps.gz) searched A007908 up to 840 terms and
found _no_ primes (I've pushed it to 1300 terms so far). Similarly, the
only prime in the first 750 terms of A000422 is the 82nd (I'm looking for
more). Am I being completely bone-headed, or is there some good reason
for this?
On another curious note, the Smarandache Function (The smallest value S(n)
for a given n for which n|S(n)! ;
http://www.astro.virginia.edu/~eww6n/math/SmarandacheFunction.html) does
not attain the following values for n=1 to 40,000: 24, 27, 30, 32, 36, 40,
42, 45, 48, 49, 50, 54, 55, 56, 60, ... Does this sequence look familar
to anyone (it doesn't appear to be in EIS)?
- -Eric
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* Eric W. Weisstein phone: (804) 924-4899 *
* U. Virginia Astron. Dept. FAX: (804) 924-3104 *
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* Charlottesville, VA 22903 WWW: http://www.astro.virginia.edu/~eww6n *
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