OFFSET
1,2
COMMENTS
A "mixed pair" happens when a(n) and a(n+1) share exactly one prime.
The sequence starts with a(1) = 1 and is always extended with the
smallest integer not yet used that doesn't lead to a contradiction.
The sequence is a permutation of the natural numbers.
LINKS
EXAMPLE
The "mixed pairs" are between parentheses:
(1,2),3,5,(7,9),4,6,8,10,12,(14,11),13,17,19,(23,18),15,16,20,21,22,24,25,26,27,28,30,32,33,34,35,(36,29),...
Listing the absolute differences of those parentheses gives: (1),(2),(3),(5),(7),... which is indeed the starting sequence.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Aug 29 2016
STATUS
approved