OFFSET
1,1
COMMENTS
This sequence is a self-inverse permutation of the natural numbers.
For any n > 0, let b(n) = a(n) - n; the sequence b is unbounded.
LINKS
EXAMPLE
The first terms of the sequence, alongside G, are:
n a(n) G(n)
-- ---- ----
1 2 1
2 1 2
3 4 2
4 3 3
5 6 3
6 5 4
7 9 4
8 10 4
9 7 5
10 8 5
11 12 5
12 11 6
13 16 6
14 17 6
15 18 6
16 13 7
17 14 7
18 15 7
19 20 7
20 19 8
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Jan 30 2019
STATUS
approved