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A238550
Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 6 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=3*floor(n/2), read by rows.
21
1, 3, 4, 1, 1, 3, 8, 3, 1, 6, 23, 33, 22, 6, 1, 1, 6, 40, 101, 125, 54, 10, 1, 9, 68, 262, 534, 532, 276, 74, 12, 1, 1, 9, 98, 509, 1551, 2505, 2196, 971, 219, 20, 1, 12, 139, 927, 3731, 8772, 12069, 9506, 4366, 1160, 179, 16, 1, 1, 12, 182, 1479, 7644, 24024
OFFSET
2,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 2..953 (terms n=2..69 from Christopher Hunt Gribble)
Christopher Hunt Gribble, C++ program
EXAMPLE
The first 6 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6 7 8 9
n
2 1 3 4 1
3 1 3 8 3
4 1 6 23 33 22 6 1
5 1 6 40 101 125 54 10
6 1 9 68 262 534 532 276 74 12 1
7 1 9 98 509 1551 2505 2196 971 219 20
PROG
(C++) See Gribble link.
KEYWORD
tabf,nonn
AUTHOR
EXTENSIONS
Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 26 2015
STATUS
approved