[seqfan] Re: swapping primes and non-primes A026234 vs A167419
franktaw at netscape.net
franktaw at netscape.net
Wed Nov 4 15:08:43 CET 2009
No, it's: if we have consecutive numbers, one prime and one non-prime,
swap them. So after the initial 2,1,4,3,6,5,8,7 it's "if n is prime,
a(n) = n-1; if n+1 is prime, a(n) = n+1, otherwise a(n) = n".
A better description might be "Exchange adjacent primes and non-primes."
Franklin T. Adams-Watters
-----Original Message-----
From: Richard Mathar <mathar at strw.leidenuniv.nl>
Is A167419 an erroneous version of A026234?
Basically I do not understand what defines A167419 . If we place
non-primes at prime indices/positions and vice versa we get A026234.
Is A167419 intending to be different if we replace "Exchange" by
something
more precise (perhaps with adjustment for inflation in the exchange
rates?)
http://research.att.com/~njas/sequences/?q=id:A026234|id:A167419
Richard
More information about the SeqFan
mailing list