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A066274
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Number of endofunctions of [n] such that 1 is not a fixed point.
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5
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0, 2, 18, 192, 2500, 38880, 705894, 14680064, 344373768, 9000000000, 259374246010, 8173092077568, 279577021469772, 10318292052303872, 408700964355468750, 17293822569102704640, 778579070010669895696, 37160496515557841043456, 1874292305362402347591138
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..300
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
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FORMULA
| a(n) = n^n - n^(n-1).
E.g.f.: T^2/(1-T), where T=T(x) is Euler's tree function (see A000169)
For n > 1 a(n)=1/(Integral_{x=n..infinity} 1/x^n dx) [From Francesco Daddi, Aug 01 2011]
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EXAMPLE
| a(2)=2: [1->2,2->1],[1->2,2->2]
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MAPLE
| with(finance):seq(futurevalue(n, n, n), n=0..16); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 25 2009]
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MATHEMATICA
| Table[(n-1)*n^(n-1), {n, 1, 20}] (* From Vladimir Joseph Stephan Orlovsky, Apr 19 2011 *)
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PROG
| (MAGMA) [n^n - n^(n-1): n in [1..20]]; // Vincenzo Librandi, Aug 02 2011
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CROSSREFS
| Cf. A045531, A066275.
Sequence in context: A183285 A129627 A138413 * A052623 A155542 A157765
Adjacent sequences: A066271 A066272 A066273 * A066275 A066276 A066277
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KEYWORD
| nonn
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AUTHOR
| Len Smiley (smiley(AT)math.uaa.alaska.edu), Dec 09 2001
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