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A238592
Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 10 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=3*floor(n/3), read by rows.
21
1, 4, 9, 2, 1, 4, 18, 8, 1, 8, 42, 28, 1, 8, 77, 165, 151, 44, 6, 1, 12, 133, 521, 891, 543, 106, 1, 12, 200, 1160, 3022, 2756, 824, 1, 16, 288, 2260, 8443, 13336, 9364, 2819, 387, 20, 1, 16, 387, 3867, 19833, 48418, 58731, 34797, 9462, 900
OFFSET
3,2
LINKS
Christopher Hunt Gribble, C++ program
EXAMPLE
The first 6 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6
n
3 1 4 9 2
4 1 4 18 8
5 1 8 42 28
6 1 8 77 165 151 44 6
7 1 12 133 521 891 543 106
8 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(36) and beyond from Andrew Howroyd, May 29 2017
STATUS
approved