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Search: id:A154825
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| A154825 |
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Reversion of x(1-2x)/(1-3x). |
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+0
2
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| 1, -1, -1, 1, 5, 3, -21, -51, 41, 391, 407, -1927, -6227, 2507, 49347, 71109, -236079, -966129, 9519, 7408497, 13685205, -32079981, -167077221, -60639939, 1209248505, 2761755543, -4457338681, -30629783831, -22124857219
(list; graph; listen)
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OFFSET
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0,5
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FORMULA
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G.f.: (1+3x-sqrt(1-2x+9x^2))/(2x);
G.f.: 1/(1+x/(1-2x/(1+x/(1-2x/(1+x/(1-2x/(1+.... (continued fraction).
a(n)=sum{k=0..n, C(n+k,2k)*A000108(k)*2^k*(-3)^(n-k)}.
a(n)=Sum_{k, 0<=k<=n}A131198(n,k)*(-1)^(n-k)*2^k = Sum_{k, 0<=k<=n}A090181(n,k)*(-1)^k*2^(n-k). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 17 2009]
a(n)=Sum_{k, 0<=k<=n}A060693(n,k)*2^(n-k)*(-3)^k = Sum_{k, 0<=k<=n}A088617(n,k)*2^k*(-3)^(n-k). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 17 2009]
a(n) = Sum_{k, 0<=k<=n}A086810(n,k)*(-1)^k*3^(n-k) = Sum_{k, 0<=k<=n}A133336(n,k)*3^k*(-1)^((n-k). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 17 2009]
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CROSSREFS
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Cf.: A091593.
Sequence in context: A084183 A099730 A072800 this_sequence A091593 A139699 A069607
Adjacent sequences: A154822 A154823 A154824 this_sequence A154826 A154827 A154828
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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), Jan 15 2009
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