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 A002525 Number of permutations according to distance. (Formerly M1203 N0463) 1
 0, 1, 2, 4, 10, 24, 55, 128, 300, 700, 1632, 3809, 8890, 20744, 48406, 112960, 263599, 615120, 1435416, 3349624, 7816528, 18240289, 42564706, 99327052, 231785058, 540883000, 1262179815, 2945365040, 6873169028, 16038912628 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Alois P. Heinz, Table of n, a(n) for n = 0..1000 Torleiv Kløve, Spheres of Permutations under the Infinity Norm - Permutations with limited displacement. Reports in Informatics, Department of Informatics, University of Bergen, Norway, no. 376, November 2008. R. Lagrange, Quelques résultats dans la métrique des permutations, Annales Scientifiques de l'École Normale Supérieure, Paris, 79 (1962), 199-241. Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992. Simon Plouffe, 1031 Generating Functions and Conjectures, Université du Québec à Montréal, 1992. FORMULA a(n) = sum(A002524(k), k=0..n-1). - Sean A. Irvine, Mar 10 2014 MAPLE A002525:=z/(1-2*z-2*z**3+z**5); # conjectured by Simon Plouffe in his 1992 dissertation MATHEMATICA a[n_ /; n <= 2] := n; a[3]=4; a[4]=10; a[n_] := a[n] = 2*a[n-1] + 2*a[n-3] - a[n-5]; Table[a[n], {n, 0, 29}] (* Jean-François Alcover, Mar 12 2014 *) PROG (PARI) a(n) = {z = x + x*O(x^n); gf = z/(1-2*z-2*z^3+z^5); polcoeff(gf, n); } \\ Michel Marcus, Mar 11 2014 CROSSREFS Sequence in context: A132732 A275447 A095214 * A159328 A190587 A190794 Adjacent sequences:  A002522 A002523 A002524 * A002526 A002527 A002528 KEYWORD nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Mar 10 2014 STATUS approved

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Last modified October 15 09:07 EDT 2018. Contains 316211 sequences. (Running on oeis4.)