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A265129
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Triangle read by rows, formed as the sum of the two versions of the natural numbers filling an equilateral triangle.
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1
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2, 5, 5, 10, 10, 10, 17, 17, 17, 17, 26, 26, 26, 26, 26, 37, 37, 37, 37, 37, 37, 50, 50, 50, 50, 50, 50, 50, 65, 65, 65, 65, 65, 65, 65, 65, 82, 82, 82, 82, 82, 82, 82, 82, 82, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101
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OFFSET
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1,1
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COMMENTS
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The natural numbers can sequentially fill a right- or left-handed equilateral triangle. Componentwise addition of the values of these two triangles produces the present triangle.
The row sums for this triangle give A034262.
The difference between the right- and left-handed triangles produces A049581.
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LINKS
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FORMULA
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T(n,k) = n^2 + 1 for k = 1..n and n >= 1. - Georg Fischer, Oct 01 2021
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EXAMPLE
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Displayed as a triangle:
2;
5 5;
10 10 10;
17 17 17 17;
26 26 26 26 26;
37 37 37 37 37 37;
...
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MAPLE
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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