login
A238557
Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 8 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=4*floor(n/2), read by rows.
21
1, 4, 9, 6, 1, 1, 4, 18, 22, 6, 1, 8, 49, 139, 204, 145, 54, 8, 1, 1, 8, 83, 392, 1056, 1438, 956, 240, 25, 1, 12, 139, 927, 3731, 8772, 12069, 9506, 4366, 1160, 179, 16, 1, 1, 12, 198, 1742, 9748, 33644, 73274, 98779, 80661, 37886, 9679, 1258, 72
OFFSET
2,2
LINKS
Christopher Hunt Gribble, C++ program
FORMULA
tabf,nonn
EXAMPLE
The first 4 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6 7 8
n
2 1 4 9 6 1
3 1 4 18 22 6
4 1 8 49 139 204 145 54 8 1
5 1 8 83 392 1056 1438 956 240 25
PROG
(C++) See Gribble link.
KEYWORD
tabf,nonn
AUTHOR
EXTENSIONS
Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 27 2015
STATUS
approved