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A108694 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. 2
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; text; internal format)
OFFSET

0,3

COMMENTS

Related to preferential arrangements of n elements (A000670) and necklaces of sets of labeled beads (A000629).

LINKS

Table of n, a(n) for n=0..35.

FORMULA

Sum_{ k>=0 } T(n, k) = n!*3^n = A032031(n).

T(n, 0) = A000670(n); T(n, n) = A000629(n).

EXAMPLE

1; 1, 2; 3, 9, 6; 13, 54, 69, 26; 75, 399, 747, 573, 150; ...

CROSSREFS

Cf. A000629, A000670, A032031, A084938.

Sequence in context: A011028 A224519 A288842 * A267896 A199858 A199963

Adjacent sequences:  A108691 A108692 A108693 * A108695 A108696 A108697

KEYWORD

easy,nonn,tabl

AUTHOR

Philippe Deléham, Jun 18 2005

STATUS

approved

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Last modified November 20 06:06 EST 2018. Contains 317385 sequences. (Running on oeis4.)