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 A001253 Number of permutations of order n with the length of longest run equal 5. (Formerly M2123 N0840) 12
 0, 0, 0, 0, 2, 20, 198, 2048, 22468, 264538, 3340962, 45173518, 652209564, 10024669626, 163546399460, 2823941647390, 51468705947590, 987671243816650, 19909066390361346, 420650676776338140, 9297308938203169622, 214562999510569012168 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 REFERENCES F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 262. (Terms for n>=13 are incorrect). 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 Max Alekseyev and Alois P. Heinz, Table of n, a(n) for n = 1..450 (first 100 terms from Max Alekseyev) Max A. Alekseyev, On the number of permutations with bounded runs length, arXiv preprint arXiv:1205.4581 [math.CO], 2012-2013. - From N. J. A. Sloane, Oct 23 2012 MATHEMATICA length = 5; g[u_, o_, t_] := g[u, o, t] = If[u+o == 0, 1, Sum[g[o + j - 1, u - j, 2], {j, 1, u}] + If[t

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Last modified July 24 05:23 EDT 2021. Contains 346273 sequences. (Running on oeis4.)