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 A000363 Number of permutations of [n] with exactly 2 increasing runs of length at least 2. (Formerly M4018 N1666) 4
 5, 61, 479, 3111, 18270, 101166, 540242, 2819266, 14494859, 73802835, 373398489, 1881341265, 9453340172, 47417364268, 237571096820, 1189405165908, 5951965440609, 29775517732665, 148927275340835, 744793282001995 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,1 REFERENCES F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 260. 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 Vincenzo Librandi, Table of n, a(n) for n = 4..1000 Index entries for linear recurrences with constant coefficients, signature (14,-75,196,-263,174,-45). FORMULA a(n) = (5^n-(2*n-1)*3^n+2*n^2-2*n-2)/16. - Vaclav Kotesovec, Nov 19 2012 G.f.: -x^4*(9*x-5)/((x-1)^3*(3*x-1)^2*(5*x-1)). - Vaclav Kotesovec, Nov 19 2012 MATHEMATICA Table[(5^n-(2*n-1)*3^n+2*n^2-2*n-2)/16, {n, 4, 20}] (* Vaclav Kotesovec, Nov 19 2012 *) PROG (Magma) [(5^n-(2*n-1)*3^n+2*n^2-2*n-2)/16: n in [4..30]]; // Vincenzo Librandi, May 03 2013 CROSSREFS Contribution from Johannes W. Meijer, May 24 2009: (Start) The a(n) sequence equals the third left hand column of A008971. The a(2*n) sequence equals the third left hand column of A160486. (End) Sequence in context: A060060 A183379 A345649 * A200956 A203358 A099666 Adjacent sequences: A000360 A000361 A000362 * A000364 A000365 A000366 KEYWORD nonn,easy AUTHOR EXTENSIONS More terms and better definition from Jon E. Schoenfield, Mar 25 2010 STATUS approved

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Last modified March 31 15:10 EDT 2023. Contains 361668 sequences. (Running on oeis4.)