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Search: id:A161556
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| A161556 |
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Exponential Riordan array [1+(sqrt(Pi)/2)*x*exp(x^2/4)*ERF(x/2),x]. |
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+0
1
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| 1, 0, 1, 1, 0, 1, 0, 3, 0, 1, 2, 0, 6, 0, 1, 0, 10, 0, 10, 0, 1, 6, 0, 30, 0, 15, 0, 1, 0, 42, 0, 70, 0, 21, 0, 1, 24, 0, 168, 0, 140, 0, 28, 0, 1, 0, 216, 0, 504, 0, 252, 0, 36, 0, 1, 120, 0, 1080, 0, 1260, 0, 420, 0, 45, 0, 1
(list; table; graph; listen)
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OFFSET
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0,8
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COMMENT
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Row sums are A084261.
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FORMULA
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Number triangle T(n,k)=[k<=n]*C(n,k)*((n-k)/2)!(1+(-1)^(n-k))/2;
G.f.: 1/(1-x*y-x^2/(1-x*y-x^2/(1-x*y-2x^2/(1-x*y-2x^2/(1-x*y-3x^2/(1-... (continued fraction).
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EXAMPLE
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Triangle begins
1,
0, 1,
1, 0, 1,
0, 3, 0, 1,
2, 0, 6, 0, 1,
0, 10, 0, 10, 0, 1,
6, 0, 30, 0, 15, 0, 1,
0, 42, 0, 70, 0, 21, 0, 1,
24, 0, 168, 0, 140, 0, 28, 0, 1
Production matrix begins
0, 1,
1, 0, 1,
0, 2, 0, 1,
-1, 0, 3, 0, 1,
0, -4, 0, 4, 0, 1,
6, 0, -10, 0, 5, 0, 1,
0, 36, 0, -20, 0, 6, 0, 1
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CROSSREFS
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Cf. A155856, A156367.
Sequence in context: A100749 A124027 A097610 this_sequence A129555 A147755 A136748
Adjacent sequences: A161553 A161554 A161555 this_sequence A161557 A161558 A161559
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Jun 13 2009
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