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A120616
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Generalized Riordan array (1/sqrt(1+4x^2),(1-sqrt(1+4x^2))/(2x)).
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1
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1, 0, -1, -2, 0, 1, 0, 3, 0, -1, 6, 0, -4, 0, 1, 0, -10, 0, 5, 0, -1, -20, 0, 15, 0, -6, 0, 1, 0, 35, 0, -21, 0, 7, 0, -1, 70, 0, -56, 0, 28, 0, -8, 0, 1, 0, -126, 0, 84, 0, -36, 0, 9, 0, -1, -252, 0, 210, 0, -120, 0, 45, 0, -10, 0, 1
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| abs(T(n,k)) is A108044. Product by A007318 is A104505.
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FORMULA
| Number triangle T(n,k)=C(n,(n+k)/2)(-1)^((n+k)/2)(1+(-1)^(n+k))/2
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EXAMPLE
| Triangle begins
.1,
.0, -1,
.-2, 0, 1,
.0, 3, 0, -1,
.6, 0, -4, 0, 1,
.0, -10, 0, 5, 0, -1,
.-20, 0, 15, 0, -6, 0, 1,
.0, 35, 0, -21, 0, 7, 0, -1,
.70, 0, -56, 0, 28, 0, -8, 0, 1,
.0, -126, 0, 84, 0, -36, 0, 9, 0, -1,
.-252, 0, 210, 0, -120, 0, 45, 0, -10, 0, 1
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CROSSREFS
| Sequence in context: A048154 A134511 A112554 * A108044 A104477 A052173
Adjacent sequences: A120613 A120614 A120615 * A120617 A120618 A120619
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KEYWORD
| easy,sign,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Jun 17 2006
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