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A238582
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Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 9 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=2*floor(n/3), read by rows.
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12
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1, 4, 6, 1, 1, 4, 12, 3, 1, 8, 28, 10, 1, 8, 54, 82, 49, 8, 1, 1, 12, 95, 283, 311, 91, 10, 1, 12, 146, 647, 1118, 451, 68, 1, 16, 212, 1300, 3380, 3076, 1200, 209, 20, 1, 1, 16, 288, 2260, 8443, 13336, 9364, 2819, 387, 20
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OFFSET
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3,2
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LINKS
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EXAMPLE
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The first 9 rows of T(n,k) are:
.\ k 0 1 2 3 4 5 6 7 8 9
n
3 1 4 6 1
4 1 4 12 3
5 1 8 28 10
6 1 8 54 82 49 8 1
7 1 12 95 283 311 91 10
8 1 12 146 647 1118 451 68
9 1 16 212 1300 3380 3076 1200 209 20 1
10 1 16 288 2260 8443 13336 9364 2819 387 20
11 1 20 379 3709 18203 42412 44599 19051 3682 282
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PROG
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(C++) See Gribble link.
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CROSSREFS
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Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550-A238552, A228166, A238555, A238556, A228167, A238557-A238559, A228168, A238581, A238583, A228169, A238586, A238592.
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KEYWORD
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tabf,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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