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Search: id:A111806
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| A111806 |
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Riordan array (1/(1+3x+2x^2),x/(1+3x+2x^2)). |
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1
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| 1, -3, 1, 7, -6, 1, -15, 23, -9, 1, 31, -72, 48, -12, 1, -63, 201, -198, 82, -15, 1, 127, -522, 699, -420, 125, -18, 1, -255, 1291, -2223, 1795, -765, 177, -21, 1, 511, -3084, 6562, -6768, 3840, -1260, 238, -24, 1, -1023, 7181, -18324, 23276, -16758, 7266, -1932, 308, -27, 1, 2047, -16398, 49029, -74616, 65870
(list; table; graph; listen)
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OFFSET
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0,2
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COMMENT
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Signed version of A110441. Factors as (1/(1+x),x/(1+x))*((1-x)/(1+x),x(1-x)/(1+x)), or inverse binomial transform of A080246. Inverse of little Schroeder number array A110440. Row sums are A108520. Diagonal sums are (-1)^n*A001906(n+1).
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EXAMPLE
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Triangle starts
1;
-3,1;
7,-6,1;
-15,23,-9,1;
31,-72,48,-12,1;
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CROSSREFS
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Sequence in context: A071043 A101624 A110441 this_sequence A054458 A110168 A046913
Adjacent sequences: A111803 A111804 A111805 this_sequence A111807 A111808 A111809
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KEYWORD
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easy,sign,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Aug 18 2005
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