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A238556
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Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 7 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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21
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1, 3, 2, 1, 3, 4, 1, 6, 9, 1, 6, 21, 13, 4, 1, 9, 39, 53, 23, 1, 9, 64, 128, 87, 1, 12, 95, 283, 311, 91, 10, 1, 12, 133, 521, 891, 543, 106, 1, 15, 177, 917, 2118, 2030, 646, 1, 15, 228, 1444, 4424, 6000, 3295, 456, 25, 1, 18, 285, 2207, 8408, 15484, 13106, 4322, 473
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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 5 rows of T(n,k) are:
./ k 0 1 2 3 4 5 6
n
3 1 3 2
4 1 3 4
5 1 6 9
6 1 6 21 13 4
7 1 9 39 53 23
8 1 9 64 128 87
9 1 12 95 283 311 91 10
10 1 12 133 521 891 543 106
11 1 15 177 917 2118 2030 646
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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, 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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