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1, 4, 3, 7, 6, 5, 10, 9, 8, 7, 13, 12, 11, 10, 9, 16, 15, 14, 13, 12, 11, 19, 18, 17, 16, 15, 14, 13, 22, 21, 20, 19, 18, 17, 16, 15, 25, 24, 23, 22, 21, 20, 19, 18, 17, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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COMMENTS
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Row sums = A000566, the heptagonal numbers: (1, 7, 18, 34, 55, ...).
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LINKS
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FORMULA
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By rows, (n+1) terms of 3n+1, 3n, 3n-1, ...
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EXAMPLE
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First few rows of the triangle:
1;
4, 3;
7, 6, 5;
10, 9, 8, 7;
13, 12, 11, 10, 9;
16, 15, 14, 13, 12, 11;
19, 18, 17, 16, 15, 14, 13;
...
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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a(5) = 5, a(30) = 20 corrected and more terms from Georg Fischer, Jun 07 2023
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STATUS
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approved
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