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 A066274 Number of endofunctions of [n] such that 1 is not a fixed point. 7
 0, 2, 18, 192, 2500, 38880, 705894, 14680064, 344373768, 9000000000, 259374246010, 8173092077568, 279577021469772, 10318292052303872, 408700964355468750, 17293822569102704640, 778579070010669895696, 37160496515557841043456, 1874292305362402347591138 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) is the number of functional digraphs that are not a solitary rooted tree. - Geoffrey Critzer, Aug 31 2013 For n > 1 a(n) is the number of numbers with n digits in base n. - Gionata Neri, Feb 18 2016 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..300 Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets 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). - Francesco Daddi, Aug 01 2011 a(n) = sum(i=1..n-1, C(n,i)*(i^i*(n-i)^(n-i-1))). - Vladimir Kruchinin May 15 2013 E.g.f.: x^2*A''(x) where A(x) is the e.g.f. for A000272. - Geoffrey Critzer, Aug 31 2013 a(n) = 2*A081131(n) = 2*|A070896(n)|. - Geoffrey Critzer, Aug 31 2013 EXAMPLE a(2)=2: [1->2,2->1], [1->2,2->2]. MAPLE with(finance): seq(futurevalue(n-1, n-1, n-1), n=1..20); # Zerinvary Lajos, Mar 25 2009 MATHEMATICA Table[(n-1)*n^(n-1), {n, 1, 20}] (* Vladimir Joseph Stephan Orlovsky, Apr 19 2011 *) PROG (MAGMA) [n^n - n^(n-1): n in [1..20]]; // Vincenzo Librandi, Aug 02 2011 CROSSREFS Cf. A045531, A066275. Sequence in context: A129627 A279860 A138413 * A052623 A155542 A157765 Adjacent sequences:  A066271 A066272 A066273 * A066275 A066276 A066277 KEYWORD nonn AUTHOR Len Smiley, Dec 09 2001 STATUS approved

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