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 A094792 a(n) = (1/n!)*A001565(n). 4
 2, 11, 32, 71, 134, 227, 356, 527, 746, 1019, 1352, 1751, 2222, 2771, 3404, 4127, 4946, 5867, 6896, 8039, 9302, 10691, 12212, 13871, 15674, 17627, 19736, 22007, 24446, 27059, 29852, 32831, 36002, 39371, 42944, 46727, 50726, 54947, 59396, 64079 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Number of injections from {1,2,3} to {1,2,...,n} with no fixed points. - Fiona T. Brunk (fbrunk(AT)mcs.st-and.ac.uk), May 23 2006 LINKS Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA a(n) = n^3 + 3*n^2 + 5*n + 2. a(n) = sum((-1)^i*binomial(3,i)*(n-i)!/(n-3)!,i=0..3). - Fiona T. Brunk (fbrunk(AT)mcs.st-and.ac.uk), May 23 2006 G.f.: (x^3+3*x+2) / (x-1)^4. - Colin Barker, Jun 15 2013 a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Fung Lam, Apr 17 2014 MAPLE with(combinat):seq(fibonacci(4, i)-1, i=1..40); # Zerinvary Lajos, Mar 20 2008 MATHEMATICA Table[n^3+3*n^2+5*n+2, {n, 0, 70}] (* Vladimir Joseph Stephan Orlovsky, May 04 2011 *) CROSSREFS Cf. A001563, A001564, A001565, A001688, A001689, A023043. Sequence in context: A183460 A033994 A023659 * A173707 A192347 A031400 Adjacent sequences:  A094789 A094790 A094791 * A094793 A094794 A094795 KEYWORD nonn,easy AUTHOR Benoit Cloitre, Jun 11 2004 STATUS approved

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Last modified January 19 06:37 EST 2020. Contains 331033 sequences. (Running on oeis4.)