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Search: id:A104733
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| A104733 |
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Triangle, row sums = number of n-node rooted trees of height 3. (A000235). |
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+0
1
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| 1, 2, 1, 4, 2, 2, 7, 4, 4, 3, 12, 7, 8, 6, 5, 20, 12, 14, 12, 10, 8, 33, 20, 24, 21, 20, 16, 13, 54, 33, 40, 36, 35, 32, 26, 21
(list; table; graph; listen)
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OFFSET
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1,2
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COMMENT
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Leftmost column of the triangle = (Fibonacci numbers minus 1). Row sums = A000235: 1, 3,8, 18, 38, 76, 147...(number of n-node rooted trees of height 3).
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FORMULA
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Extract the triangle from A * B, A = [1; 1, 1; 2, 1, 1; 3, 2, 1, 1;...]; B = [1; 1, 1; 1, 1, 2; 1, 1, 2, 3;...]; both infinite lower triangular matrices having Fibonacci numbers in every row (and all the rest of the terms zeros).
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EXAMPLE
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The first few rows of the triangle are:
1;
2, 1;
4, 2, 2;
7, 4, 4, 3;
12, 7, 8, 6, 5;
20, 12, 14, 12, 10, 8
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CROSSREFS
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Cf. A000235.
Sequence in context: A136693 A086685 A094571 this_sequence A153281 A130584 A078458
Adjacent sequences: A104730 A104731 A104732 this_sequence A104734 A104735 A104736
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KEYWORD
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nonn,uned,tabl
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 20 2005
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