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A122919
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Inverse of Riordan array (1/(1+x+x^2),x/(1+x)^2).
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2
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1, 1, 1, 3, 3, 1, 9, 10, 5, 1, 28, 34, 21, 7, 1, 90, 117, 83, 36, 9, 1, 297, 407, 319, 164, 55, 11, 1, 1001, 1430, 1209, 702, 285, 78, 13, 1, 3432, 5070, 4550, 2898, 1350, 454, 105, 15, 1, 11934, 18122, 17068, 11696, 6052
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| Row sums are A097613. Diagonal sums are A122920. Inverse of A122917.
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FORMULA
| Riordan array ((1-3x+2x^2-(1-x)sqrt(1-4x))/(2x^2),(1-2x-sqrt(1-4x))/(2x))
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EXAMPLE
| Triangle begins
1,
1, 1,
3, 3, 1,
9, 10, 5, 1,
28, 34, 21, 7, 1,
90, 117, 83, 36, 9, 1,
297, 407, 319, 164, 55, 11, 1,
1001, 1430, 1209, 702, 285, 78, 13, 1
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CROSSREFS
| Sequence in context: A193824 A108075 A084145 * A188513 A157401 A143911
Adjacent sequences: A122916 A122917 A122918 * A122920 A122921 A122922
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Sep 19 2006
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