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Search: id:A098336
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| A098336 |
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Expansion of 1/sqrt(1-4x+12x^2). |
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+0
4
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| 1, 2, 0, -16, -56, -48, 384, 1920, 3168, -8512, -66560, -161280, 113920, 2224640, 7311360, 3354624, -69253632, -306754560, -408059904, 1898029056, 12054196224, 25377005568, -38874316800, -443400781824, -1289598418944
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Central coefficients of (1+2x-2x^2)^n. Binomial transform of A098332.
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REFERENCES
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Tony D. Noe, On the Divisibility of Generalized Central Trinomial Coefficients, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.7.
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FORMULA
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E.g.f. : exp(2x)BesselI(0, 2sqrt(-2)x); a(n)=sum{k=0..floor(n/2), binomial(n, k)binomial(n-k, k)2^n(-2)^(-k)}.
a(n)=sum{k=0..floor(n/2), binomial(n, k)binomial(2(n-k), k)(-3)^k} - Paul Barry (pbarry(AT)wit.ie), Sep 08 2004
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CROSSREFS
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Sequence in context: A009266 A009246 A012414 this_sequence A116093 A012409 A012661
Adjacent sequences: A098333 A098334 A098335 this_sequence A098337 A098338 A098339
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KEYWORD
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easy,sign
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Sep 03 2004
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