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A256258
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Triangle read by rows in which the row lengths are the terms of A011782 and row n lists the terms of A016969 except for the right border which gives the positive terms of A000225.
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6
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1, 3, 5, 7, 5, 11, 17, 15, 5, 11, 17, 23, 29, 35, 41, 31, 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 63, 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 95, 101, 107, 113, 119, 125, 131, 137, 143, 149, 155, 161, 167, 173, 179, 185, 127, 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 95, 101, 107, 113, 119, 125, 131, 137
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OFFSET
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1,2
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COMMENTS
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The sum of all terms of first n rows gives A000302(n-1).
The rows of triangle A256263 converge to this sequence.
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LINKS
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EXAMPLE
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Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
3;
5,7;
5,11,17,15;
5,11,17,23,29,35,41,31;
5,11,17,23,29,35,41,47,53,59,65,71,77,83,89,63;
5,11,17,23,29,35,41,47,53,59,65,71,77,83,89,95,101,107,113,119,125,131,137,143,149,155,161,167,173,179,185,127;
...
Illustration of initial terms in the fourth quadrant of the square grid:
------------------------------------------------------------------------
n a(n) Compact diagram
------------------------------------------------------------------------
. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
1 1 |_| | | |_ _ | |_ _ _ _ _ _ | |
2 3 |_ _| | |_ | | |_ _ _ _ _ | | |
3 5 |_ _ _| | | | | |_ _ _ _ | | | |
4 7 |_ _ _ _| | | | |_ _ _ | | | | |
5 5 | | |_ _ _| | | |_ _ | | | | | |
6 11 | |_ _ _ _ _| | |_ | | | | | | |
7 17 |_ _ _ _ _ _ _| | | | | | | | | |
8 15 |_ _ _ _ _ _ _ _| | | | | | | | |
9 5 | | | | | | |_ _ _| | | | | | | |
10 11 | | | | | |_ _ _ _ _| | | | | | |
11 17 | | | | |_ _ _ _ _ _ _| | | | | |
12 23 | | | |_ _ _ _ _ _ _ _ _| | | | |
13 29 | | |_ _ _ _ _ _ _ _ _ _ _| | | |
14 35 | |_ _ _ _ _ _ _ _ _ _ _ _ _| | |
15 41 |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _| |
16 31 |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|
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a(n) is also the number of cells in the n-th region of the diagram.
It appears that A241717 can be represented by a similar diagram.
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MATHEMATICA
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Nest[Join[#, Range[Length[#] - 1]*6 - 1, {2 #[[-1]] + 1}] &, {1}, 7] (* Ivan Neretin, Feb 14 2017 *)
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CROSSREFS
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Cf. A000225, A000302, A002001, A011782, A016969, A141548, A241717, A256260, A256261, A256263, A256264.
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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