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Search: id:A143971
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| A143971 |
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Triangle read by rows, (3n-2) subsequences decrescendo |
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+0
2
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| 1, 4, 1, 7, 4, 1, 10, 7, 4, 1, 13, 10, 7, 4, 1, 16, 3, 10, 7, 4, 1, 19, 16, 13, 10, 7, 4, 1, 22, 19, 16, 13, 10, 7, 4, 1, 25, 2, 19, 16, 13, 10, 7, 4, 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 = pentagonal numbers, A000326: (1, 5, 12, 22, 35,...).
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FORMULA
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Triangle read by rows, (3n-2) subsequences decrescendo; 1<=k<=n.
(1, 4, 7, 10, 13,...) in every column.
T(n,k) = f(x), (3*x - 2), x = (n-k+1).
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EXAMPLE
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First few rows of the triangle =
1;
4, 1;
7, 4, 1;
10, 7, 4, 1;
Example: T(6,2) = 13; (n-k+1) = 5 = x, then (3*x - 2) = 13.
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CROSSREFS
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A016777, A000326
Sequence in context: A158860 A037022 A037023 this_sequence A016688 A143972 A019651
Adjacent sequences: A143968 A143969 A143970 this_sequence A143972 A143973 A143974
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KEYWORD
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nonn,tabl
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 06 2008
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