[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 
more precise (perhaps with adjustment for inflation in the exchange 



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