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A238558
Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 8 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, 3, 4, 1, 3, 8, 1, 6, 18, 1, 6, 36, 32, 13, 1, 9, 64, 128, 87, 1, 9, 100, 308, 332, 1, 12, 146, 647, 1118, 451, 68, 1, 12, 200, 1160, 3022, 2756, 824, 1, 15, 264, 1958, 6882, 10076, 5009, 1, 15, 336, 3020, 13798, 28774, 24237, 4774, 346
OFFSET
3,2
LINKS
Christopher Hunt Gribble, C++ program
EXAMPLE
The first 8 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6
n
3 1 3 4
4 1 3 8
5 1 6 18
6 1 6 36 32 13
7 1 9 64 128 87
8 1 9 100 308 332
9 1 12 146 647 1118 451 68
10 1 12 200 1160 3022 2756 824
PROG
(C++) See Gribble link.
KEYWORD
tabf,nonn
AUTHOR
EXTENSIONS
Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 27 2015
Terms a(41) and beyond from Andrew Howroyd, May 29 2017
STATUS
approved