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Search: id:A104792
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| A104792 |
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Triangle T(n,k) = A000330(n-k), n>=1, 0<=k<n, read by rows. |
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+0
1
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| 1, 5, 1, 14, 5, 1, 30, 14, 5, 1, 55, 30, 14, 5, 1, 91, 55, 30, 14, 5, 1, 140, 91, 55, 30, 14, 5, 1, 204, 140, 91, 55, 30, 14, 5, 1, 285, 204, 140, 91, 55, 30, 14, 5, 1, 385, 285, 204, 140, 91, 55, 30, 14, 5, 1, 506, 385, 285, 204, 140, 91, 55, 30, 14, 5, 1, 650, 506, 385, 285
(list; table; graph; listen)
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OFFSET
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1,2
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COMMENT
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Repeatedly writing the square pyramidal numbers (A000330) backwards.
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FORMULA
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T(n,k) = (n-k)(n-k+1)(2n-2k+1)/6 = A000330(A004736(n)). -- R. Stephan, Apr 05 2009
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EXAMPLE
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First few rows of the triangle are:
1;
5, 1;
14, 5, 1;
30, 14, 5, 1;
55, 30, 14, 5, 1;
91, 55, 30, 14, 5, 1;
...
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CROSSREFS
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Row sums are in A002415. Antidiagonals are in A000332.
Sequence in context: A147004 A146620 A067558 this_sequence A120393 A094368 A087727
Adjacent sequences: A104789 A104790 A104791 this_sequence A104793 A104794 A104795
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KEYWORD
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nonn,easy,tabl
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 26 2005
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EXTENSIONS
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Edited by Ralf Stephan, Apr 05 2009
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