[seqfan] Re: A098550.
L. Edson Jeffery
lejeffery2 at gmail.com
Tue Dec 2 05:17:47 CET 2014
Also, two more related sequences could be added to the database, if there
is any interest:
(1) Restricting to the odd natural numbers,
A(n) = 2*n-1, if n <= 3;
A(n) = least odd k not already in A such that GCD(k,A(n-1))=1 and
GCD(k,A(n-2))>1, otherwise.
A begins
{1, 3, 5, 9, 25, 21, 55, 7, 11, 35, 33, 49, 15, 77, 27, 91, 45, 13, ...},
and is conjectured to be a permutation of the odd natural numbers.
(2) Then there is the "index" sequence B corresponding to A:
B(n) = (A(n)+1)/2.
B begins
{1, 2, 3, 5, 13, 11, 28, 4, 6, 18, 17, 25, 8, 39, 14, 46, 23, 7, ...},
and is conjectured to be a permutation of the natural numbers.
I would prefer to leave this project for someone with a better grasp of
A098550.
Ed Jeffery
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