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Search: id:A131821
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| A131821 |
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A130296 + A051340 - A000012 as infinite lower triangular matrices. Triangle read by rows: row n consists of n followed by (n-2) ones then n. |
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+0
13
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| 1, 2, 2, 3, 1, 3, 4, 1, 1, 4, 5, 1, 1, 1, 5, 6, 1, 1, 1, 1, 6, 7, 1, 1, 1, 1, 1, 7, 8, 1, 1, 1, 1, 1, 1, 8, 9, 1, 1, 1, 1, 1, 1, 1, 9, 10, 1, 1, 1, 1, 1, 1, 1, 1, 10, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 14, 1, 1, 1, 1, 1, 1, 1, 1, 1
(list; table; graph; listen)
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OFFSET
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1,2
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COMMENT
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Row sums = A016777: (1, 4, 7, 10, 13,...).
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EXAMPLE
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First few rows of the triangle are:
1;
2, 2;
3, 1, 3;
4, 1, 1, 4;
5, 1, 1, 1, 5;
6, 1, 1, 1, 1, 6;
7, 1, 1, 1, 1, 1, 7;
...
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MAPLE
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A131821 := proc(n, c) if c=1 or c=n then n ; else 1 ; fi ; end: for n from 1 to 16 do for c from 1 to n do printf("%d, ", A131821(n, c)) ; od: od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 30 2008
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CROSSREFS
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Cf. A130296, A051340, A016777.
Sequence in context: A135621 A077268 A162911 this_sequence A143182 A128715 A113881
Adjacent sequences: A131818 A131819 A131820 this_sequence A131822 A131823 A131824
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KEYWORD
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nonn,tabl,easy
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Jul 19 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 30 2008
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