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A055214
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a(n) = 2n*a(n-1) - 1.
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0
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1, 1, 3, 17, 135, 1349, 16187, 226617, 3625871, 65265677, 1305313539, 28716897857, 689205548567, 17919344262741, 501741639356747, 15052249180702409, 481671973782477087, 16376847108604220957
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| a(n) is a specific instance of a classs of sequences s(0)= a, s(n) = 2*s(n-1)+k which have an explicit form of 2^n*n!*a + floor(2^n*n!*(e^(1/2)+1))*k [From Gary Detlefs (gdetlefs(AT)aol.com), Jul 18 2010]
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FORMULA
| a(n) = ceiling[2^n * n! * (2-sqrt(e))] = ceiling[A000165(n) * (2-sqrt(e))]
a(n) = 2^n*n! - floor(2^n*n!*(e^(1/2)+1)) [From Gary Detlefs (gdetlefs(AT)aol.com), Jul 18 2010]
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EXAMPLE
| a(3) = 2*3*a(2)-1 = 6*3-1 = 17
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MATHEMATICA
| s=-1; lst={Abs[s]}; Do[s+=s++n; AppendTo[lst, Abs[s]], {n, 1, 5!, 2}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 23 2008]
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CROSSREFS
| Sequence in context: A163684 A093986 A192459 * A105630 A199138 A006290
Adjacent sequences: A055211 A055212 A055213 * A055215 A055216 A055217
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KEYWORD
| easy,nonn
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AUTHOR
| Henry Bottomley (se16(AT)btinternet.com), Jun 19 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 04 2000
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