login
A238582
Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 9 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=2*floor(n/3), read by rows.
12
1, 4, 6, 1, 1, 4, 12, 3, 1, 8, 28, 10, 1, 8, 54, 82, 49, 8, 1, 1, 12, 95, 283, 311, 91, 10, 1, 12, 146, 647, 1118, 451, 68, 1, 16, 212, 1300, 3380, 3076, 1200, 209, 20, 1, 1, 16, 288, 2260, 8443, 13336, 9364, 2819, 387, 20
OFFSET
3,2
LINKS
Christopher Hunt Gribble, C++ program
EXAMPLE
The first 9 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6 7 8 9
n
3 1 4 6 1
4 1 4 12 3
5 1 8 28 10
6 1 8 54 82 49 8 1
7 1 12 95 283 311 91 10
8 1 12 146 647 1118 451 68
9 1 16 212 1300 3380 3076 1200 209 20 1
10 1 16 288 2260 8443 13336 9364 2819 387 20
11 1 20 379 3709 18203 42412 44599 19051 3682 282
PROG
(C++) See Gribble link.
KEYWORD
tabf,nonn
AUTHOR
EXTENSIONS
Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 27 2015
Terms a(46) and beyond from Andrew Howroyd, May 29 2017
STATUS
approved