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A124744
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Expansion of (1+x*y)/(1-x^2*y^2+x^3*y^2).
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4
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1, 0, 1, 0, 0, 1, 0, 0, -1, 1, 0, 0, 0, -1, 1, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 1, -2, 1, 0, 0, 0, 0, 0, 1, -3, 1, 0, 0, 0, 0, 0, 0, 3, -3, 1, 0, 0, 0, 0, 0, 0, -1, 3, -4, 1, 0, 0, 0, 0, 0, 0, 0, -1, 6, -4, 1
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,20
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COMMENTS
| Row sums are A124745. Diagonal sums are A124746. Inverse is A124747.
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FORMULA
| Number triangle T(n,k)=C(floor(k/2),n-k)*(-1)^(n-k)
Column k has g.f. x^k*(1-x)^floor(k/2). - Paul Barry (pbarry(AT)wit.ie), Feb 01 2007
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EXAMPLE
| Triangle begins
1,
0, 1,
0, 0, 1,
0, 0, -1, 1,
0, 0, 0, -1, 1,
0, 0, 0, 0, -2, 1,
0, 0, 0, 0, 1, -2, 1,
0, 0, 0, 0, 0, 1, -3, 1,
0, 0, 0, 0, 0, 0, 3, -3, 1,
0, 0, 0, 0, 0, 0, -1, 3, -4, 1,
0, 0, 0, 0, 0, 0, 0, -1, 6, -4, 1
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CROSSREFS
| Sequence in context: A143542 A072612 A116378 * A124788 A017857 A127842
Adjacent sequences: A124741 A124742 A124743 * A124745 A124746 A124747
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KEYWORD
| easy,sign,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Nov 06 2006
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