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A108206
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a(n)= 3*(n-1)*a(n-1) +(n-1)*a(n-2), with a(0)=1, a(1)=1.
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0
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0, 1, 3, 20, 189, 2348, 36165, 665058, 14219373, 346585416, 9485780589, 288039271830, 9609639556869, 349403495309244, 13751661631299813, 582461437448921562, 26417039609670967485, 1277337284263389184272
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| This is also the (2,2) element of the product matrix after multiplying the unit matrix from the
left by the matrices (0,1;j-1,3j-3) in the order j=2 to n.
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MATHEMATICA
| M[n_] := {{0, 1}, {(n - 1), 3*(n - 1)}} v[1] = {0, 1} v[n_] := v[n] = M[n].v[n - 1] a = Table[Abs[v[n][[1]]], {n, 1, 25}]
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CROSSREFS
| Cf. A000166.
Sequence in context: A065980 A073767 A176043 * A120485 A087152 A158833
Adjacent sequences: A108203 A108204 A108205 * A108207 A108208 A108209
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KEYWORD
| nonn,easy
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AUTHOR
| Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 15 2005
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EXTENSIONS
| Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009
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