[seqfan] Biprimes of K
Eric Angelini
Eric.Angelini at kntv.be
Wed Sep 17 00:22:45 CEST 2014
Hello SeqFans,
what are the "biprimes" of K?
K = http://oeis.org/A026242
K = 1, 1, 2, 3, 2, 4, 3, 5, 6, 4, 7, 8, 5, 9, 6, 10, 11, 7, 12, 8, 13, 14, 9, 15, 16, 10, 17, 11, 18, 19, 12, 20, 21, 13, 22, 14, 23, 24, 15, 25, 16, 26, 27, 17, 28, 29, 18, 30, 19, 31, 32, 20, 33, 21, 34, 35, 22, 36, 37, 23, 38, 24, 39, 40, 25, 41, ...
Let's start with the first "2" of K
and underline one on two terms
(this is 2-3-6-7-5-...)
We then go back to the first "3"
and underline one on three terms
(this is 3-4-5-10-12-...)
We then go back to the first "4"
and underline one on four terms
(this is 4-9-7-14-...)
We then go back to the first "5"
and underline one on five terms
(this is 5-7-9-11-...)
etc.
At the end, we will see that some
terms are not underlined: the
"biprimes" of K.
BIP = 2,3,4,5,8,15,...
What are the next ones (if there are)?
Best,
É.
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