OFFSET
1,2
COMMENTS
A fractal sequence: if you delete the first occurrence of each positive
integer, the remaining sequence is the original. This procedure is called
upper trimming, in contrast to lower trimming, which consists of
subtracting 1 from each term of the original fractal sequence and then
deleting all 0's. In general, the lower trim of a fractal sequence is a
REFERENCES
Clark Kimberling, "Fractal Sequences and Interspersions," Ars Combinatoria 45 (1997) 157-168.
FORMULA
EXAMPLE
The first 7 rows in the construction of A003603 are
1
1
1 2
1 3 2
1 4 3 2 5
1 6 4 3 7 2 8 5
1 9 6 4 10 3 11 7 2 12 8 5 13
Subtracting 1 and deleting 0's leaves
1
2 1
3 2 1 4
5 4 2 6 1 7 4
8 5 3 9 2 10 6 1 11 7 4 12
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Oct 31 2009
STATUS
approved