OFFSET
1,4
COMMENTS
We tile the first quadrant according to the following rules:
(a) We use bricks of height 1 and width 1, 2, 3, ...
(b) The bricks are laid by increasing size, without overlap.
(c) The left border of any brick must lie on the Y-axis or match the right border of a smaller brick.
(d) The bottom border of any brick must lie on the X-axis or touch all along the top border of smaller bricks.
(e) When multiple positions are possible, we choose the leftmost one.
A233381 gives the Y-coordinate.
LINKS
Paul Tek, Table of n, a(n) for n = 1..10000
Paul Tek, PERL program for this sequence
Paul Tek, Illustration of the first 1022 bricks
Paul Tek, Illustration of the first 9986 bricks
EXAMPLE
The following diagram depicts the first 7 bricks:
+-------------+
| 7 |
+-----+-------+---+
| 3 | 6 |
+-+---+-------+---+-----+
|1| 2 | 4 | 5 |
+-+---+-------+---------+---> X
0 1 2 3 4 5 6 7 8 9 ...
Hence:
a(1)=a(3)=a(7)=0
a(2)=1
a(4)=a(6)=3
a(5)=7
PROG
(Perl) See Link section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Tek, Dec 08 2013
STATUS
approved