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A238189
Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 4 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=n-n%2, read by rows.
21
1, 2, 1, 1, 2, 2, 1, 4, 7, 3, 1, 1, 4, 13, 10, 4, 1, 6, 23, 33, 22, 6, 1, 1, 6, 34, 68, 72, 30, 6, 1, 8, 49, 139, 204, 145, 54, 8, 1, 1, 8, 65, 230, 467, 476, 269, 70, 9, 1, 10, 85, 377, 961, 1348, 1080, 472, 111, 12, 1, 1, 10, 106, 552, 1767, 3188, 3454, 2156
OFFSET
2,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 2..967 (terms n=2..127 from Christopher Hunt Gribble)
Christopher Hunt Gribble, C++ program
EXAMPLE
The first 10 rows of T(n,k) are:
k 0 1 2 3 4 5 6 7 8 9 10
n
2 1 2 1
3 1 2 2
4 1 4 7 3 1
5 1 4 13 10 4
6 1 6 23 33 22 6 1
7 1 6 34 68 72 30 6
8 1 8 49 139 204 145 54 8 1
9 1 8 65 230 467 476 269 70 9
10 1 10 85 377 961 1348 1080 472 111 12 1
11 1 10 106 552 1767 3188 3454 2156 779 140 12
PROG
(C++) See Gribble link.
KEYWORD
tabf,nonn
AUTHOR
EXTENSIONS
Terms corrected and extended by Christopher Hunt Gribble, Apr 25 2015
STATUS
approved