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A108694
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Triangle T(n,k), 0<=k<=n, read by rows, given by [1, 2, 2, 4, 3, 6, 4, 8, 5, 10, 6, 12, . . . ] DELTA [2, 1, 4, 2, 6, 3, 8, 4, 10, 5, 12, 6, . . . ] where DELTA is the operator defined in A084938.
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2
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1, 1, 2, 3, 9, 6, 13, 54, 69, 26, 75, 399, 747, 573, 150, 541, 3508, 8638, 9998, 5393, 1082, 4683, 35817, 109248, 169038, 139143, 57585, 9366, 47293, 416762, 1515531, 2935222, 3256907, 2064534, 691645, 94586
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Related to preferential arrangements of n elements (A000670) and necklaces of sets of labeled beads (A000629).
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FORMULA
| Sum_{ k>=0 } T(n, k) = n!*3^n = A032031(n).
T(n, 0) = A000670(n); T(n, n) = A000629(n).
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EXAMPLE
| 1; 1, 2; 3, 9, 6; 13, 54, 69, 26; 75, 399, 747, 573, 150; ...
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CROSSREFS
| Cf. A000629, A000670, A032031, A084938.
Sequence in context: A082234 A168221 A011028 * A199858 A199963 A016634
Adjacent sequences: A108691 A108692 A108693 * A108695 A108696 A108697
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jun 18 2005
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