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Search: id:A026780
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| A026780 |
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Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; for n >= 2 and 1<=k<=n-1, T(n,k)=T(n-1,k-1)+T(n-2,k-1)+T(n-1,k) if 1<=k<=[ n/2 ], else T(n,k)=T(n-1,k-1)+T(n-1,k). |
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30
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| 1, 1, 1, 1, 3, 1, 1, 5, 4, 1, 1, 7, 12, 5, 1, 1, 9, 24, 17, 6, 1, 1, 11, 40, 53, 23, 7, 1, 1, 13, 60, 117, 76, 30, 8, 1, 1, 15, 84, 217, 246, 106, 38, 9, 1, 1, 17, 112, 361, 580, 352, 144, 47, 10, 1, 1, 19, 144, 557, 1158, 1178, 496, 191, 57, 11
(list; table; graph; listen)
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OFFSET
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1,5
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FORMULA
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T(n, k) = number of paths from (0, 0) to (n-k, k) in the directed graph having vertices (i, j) and edges (i, j)-to-(i+1, j) and (i, j)-to-(i, j+1) for i, j >= 0 and edges (i, i+h)-to-(i+1, i+h+1) for i >= 0, h>=0.
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CROSSREFS
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Adjacent sequences: A026777 A026778 A026779 this_sequence A026781 A026782 A026783
Sequence in context: A114278 A134836 A131767 this_sequence A026703 A122917 A096583
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KEYWORD
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nonn,tabl
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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