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 A000505 Eulerian numbers (Euler's triangle: column k=5 of A008292, column k=4 of A173018). (Formerly M5317 N2310) 9
 1, 57, 1191, 15619, 156190, 1310354, 9738114, 66318474, 423281535, 2571742175, 15041229521, 85383238549, 473353301060, 2575022097600, 13796160184500, 73008517581444, 382493246941965, 1987497491971605, 10258045633638475 (list; graph; refs; listen; history; text; internal format)
 OFFSET 5,2 COMMENTS There are 2 versions of Euler's triangle: * A008292 Classic version of Euler's triangle used by Comtet (1974). * A173018 Version of Euler's triangle used by Graham, Knuth and Patashnik in Concrete Math. (1990). Euler's triangle rows and columns indexing conventions: * A008292 The rows and columns of the Eulerian triangle are both indexed starting from 1. (Classic version: used in the classic books by Riordan and Comtet.) * A173018 The rows and columns of the Eulerian triangle are both indexed starting from 0. (Graham et al.) Number of permutations of n letters with exactly 4 descents. - Neven Juric, Jan 21 2010 REFERENCES L. Comtet, "Permutations by Number of Rises; Eulerian Numbers." §6.5 in Advanced Combinatorics: The Art of Finite and Infinite Expansions, rev. enl. ed. Dordrecht, Netherlands: Reidel, pp. 51 and 240-246, 1974. L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 243. F. N. David and D. E. Barton, Combinatorial Chance. Hafner, NY, 1962, p. 151. F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 260. J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 215. 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 G. C. Greubel, Table of n, a(n) for n = 5..1000 L. Carlitz et al., Permutations and sequences with repetitions by number of increases, J. Combin. Theory, 1 (1966), 350-374. E. T. Frankel, A calculus of figurate numbers and finite differences, American Mathematical Monthly, 57 (1950), 14-25. [Annotated scanned copy] J. Riordan, Review of Frankel (1950) [Annotated scanned copy] R. G. Wilson, V, Letter to N. J. A. Sloane, Apr. 1994 FORMULA a(n) = 5^(n + 4) - (n + 5)*4^(n + 4) + (1/2)*(n + 4)*(n + 5)*3^(n + 4) - (1/6)*(n + 3)*(n + 4)*(n + 5)*2^(n + 4) + (1/24)*(n + 2)*(n + 3)*(n + 4)*(n + 5). - Randall L Rathbun, Jan 22 2002 E.g.f.: (1/24)*exp(x)*(x^4 + 8*x^3 + 12*x^2) - 4*exp(2*x)*(2*x^3/3 + 2*x^2 + x) + 3*exp(3*x)*(9*x^2/2 + 6*x + 1) - 8*exp(4*x)*(2*x + 1) + 5*exp(5*x). - Wenjin Woan, Oct 21 2007 G.f.: (1 + 22*x - 244*x^2 + 422*x^3 + 2575*x^4 - 12012*x^5 + 17828*x^6 - 5664*x^7 - 9552*x^8 + 6912*x^9)*(x/(1-x))^5 / Product_{j=1..4} (1 - (6-j)*x)^j. See the recurrence given in an Apr 03 2017 comment on A123125. - Wolfdieter Lang, Apr 03 2017 MATHEMATICA k = 5; Table[k^(n + k - 1) + Sum[(-1)^i/i!*(k - i)^(n + k - 1) * Product[n + k + 1 - j, {j, 1, i}], {i, 1, k - 1}], {n, 1, 19}] (* Michael De Vlieger, Aug 04 2015, after PARI at A001243 *) a[n_] := 5^n - 2^(n-1)*n*(n^2-1)/3 - 4^n*(n+1) + 3^n*n*(n+1)/2 + (n-2)* (n-1)*n*(n+1)/24; Table[a[n], {n, 5, 25}] (* Jean-François Alcover, Feb 09 2016 *) PROG (PARI) A(n)=5^(n+4)-(n+5)*4^(n+4)+1/2*(n+4)*(n+5)*3^(n+4)-1/6*(n+3)*(n+4)*(n+5)*2^(n+4)+1/24*(n+2)*(n+3)*(n+4)*(n+5) (Magma) [5^(n + 4) - (n + 5)*4^(n + 4) + (1/2)*(n + 4)*(n + 5)*3^(n + 4) - (1/6)*(n + 3)*(n + 4)*(n + 5)*2^(n + 4) + (1/24)*(n + 2)*(n + 3)*(n + 4)*(n + 5): n in [5..25]]; // G. C. Greubel, Oct 23 2017 CROSSREFS Cf. A008292 (classic version of Euler's triangle used by Comtet (1974)). Cf. A173018 (version of Euler's triangle used by Graham, Knuth and Patashnik in Concrete Math. (1990)). Cf. A123125 (row reversed Euler's triangle). Cf. A000012, A000460, A000498 (columns for smaller k). Sequence in context: A336734 A333109 A208601 * A332911 A179466 A345457 Adjacent sequences: A000502 A000503 A000504 * A000506 A000507 A000508 KEYWORD nonn,easy AUTHOR EXTENSIONS More terms from Christian G. Bower, May 12 2000 STATUS approved

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Last modified January 30 14:06 EST 2023. Contains 359945 sequences. (Running on oeis4.)