[seqfan] Re: A167827 Prime numbers such that the hexadecimal representation use only the digits A, B, C, D, E, F (and not the decimal digits).

franktaw at netscape.net franktaw at netscape.net
Fri Nov 13 21:42:33 CET 2009


Yes, the sequence is just plain wrong.  See the comment claiming 113 in 
hex is AD; whereas it is actually 71, as you note.  (I can sort of see 
how one might think 113 is AD; but I'm totally mystified by the claim 
that 131 is BB.)

This makes it an incorrect version of A140969.  I'm not entirely sure 
whether it should be marked dead or simply deleted.

Incidentally, I don't think A140969 should have the "word" keyword.

Franklin T. Adams-Watters

-----Original Message-----
From: Jonathan Post <jvospost3 at gmail.com>

I'm having problems with
A167827         Prime numbers such that the hexadecimal representation 
use
only the digits A,B,C,D,E,F (and not the decimal digits).

To start, using the U.Nice base converter,
http://wims.unice.fr/wims/wims.cgi
I get:

a(3) = 113 base 10 = 71 (base 16)  which checks because (7 * 16) + 1 =
113, granted 71 (base 10) is also prime, but is not "letters"
a(4) = 131 base 10 = 83 (base 16) which is also prime as 83(base 10)
but not "letters"

I was expecting something that I could intersect with

A132675     Decimal number representations of hexadecimal numbers whose
form spells an American-English word found in a standard dictionary in
lexicographic order.

In that latter seq, the first primes (as read in base 10) seems to be:
A132675 (8) = 44269
A132675 (9) = 173
no more through
A132675 (33) .




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