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A014413
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Triangular array formed from elements to right of middle of Pascal's triangle.
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7
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1, 1, 3, 1, 4, 1, 10, 5, 1, 15, 6, 1, 35, 21, 7, 1, 56, 28, 8, 1, 126, 84, 36, 9, 1, 210, 120, 45, 10, 1, 462, 330, 165, 55, 11, 1, 792, 495, 220, 66, 12, 1, 1716, 1287, 715, 286, 78, 13, 1, 3003, 2002, 1001, 364, 91, 14, 1, 6435, 5005, 3003, 1365, 455, 105, 15, 1
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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LINKS
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EXAMPLE
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1;
1;
3, 1;
4, 1;
10, 5, 1;
15, 6, 1;
35, 21, 7, 1;
56, 28, 8, 1;
126, 84, 36, 9, 1;
210, 120, 45, 10, 1;
462, 330, 165, 55, 11, 1;
792, 495, 220, 66, 12, 1.
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PROG
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(Haskell)
a014413 n k = a014413_tabf !! (n-1) !! (k-1)
a014413_row n = a014413_tabf !! (n-1)
a014413_tabf = [1] : f 1 [1] where
f 0 us'@(_:us) = ys : f 1 ys where
ys = zipWith (+) us' (us ++ [0])
f 1 vs@(v:_) = ys' : f 0 ys where
ys@(_:ys') = zipWith (+) (vs ++ [0]) ([v] ++ vs)
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CROSSREFS
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KEYWORD
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tabf,nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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