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 A000498 Eulerian numbers (Euler's triangle: column k=4 of A008292, column k=3 of A173018) (Formerly M5188 N2255) 9
 1, 26, 302, 2416, 15619, 88234, 455192, 2203488, 10187685, 45533450, 198410786, 848090912, 3572085255, 14875399450, 61403313100, 251732291184, 1026509354985, 4168403181210, 16871482830550, 68111623139600 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,2 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 3 descents. 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 T. D. Noe, Table of n, a(n) for n = 4..200 E. Banaian, S. Butler, C. Cox, J. Davis, J. Landgraf and S. Ponce A generalization of Eulerian numbers via rook placements, arXiv:1508.03673 [math.CO], 2015. L. Carlitz et al., Permutations and sequences with repetitions by number of increases, J. Combin. Theory, 1 (1966), 350-374. F. N. Castro, O. E. González, L. A. Medina, The p-adic valuation of Eulerian numbers: trees and Bernoulli numbers, 2014. E. T. Frankel, A calculus of figurate numbers and finite differences, American Mathematical Monthly, 57 (1950), 14-25. [Annotated scanned copy] J. C. P. Miller, Letter to N. J. A. Sloane, Mar 26 1971 Nagatomo Nakamura, Pseudo-Normal Random Number Generation via the Eulerian Numbers, Josai Mathematical Monographs, vol. 8, p 85-95, 2015. P. A. Piza, Kummer numbers, Mathematics Magazine, 21 (1947/1948), 257-260. P. A. Piza, Kummer numbers, Mathematics Magazine, 21 (1947/1948), 257-260. [Annotated scanned copy] J. Riordan, Review of Frankel (1950) [Annotated scanned copy] Eric Weisstein's World of Mathematics, Eulerian Number R. G. Wilson, V, Letter to N. J. A. Sloane, Apr. 1994 Index entries for linear recurrences with constant coefficients, signature (20, -175, 882, -2835, 6072, -8777, 8458, -5204, 1848, -288). FORMULA From Mike Zabrocki, Nov 12 2004: (Start) G.f.: x^4*(1 +6*x -43*x^2 +44*x^3 +52*x^4 -72*x^5)/((1-x)^4*(1-2*x)^3*(1-3*x)^2*(1-4*x)). a(n) = (6*4^n - 6*(n + 1)*3^n + 3*(n)*(n + 1)*2^n - (n - 1)*(n)*(n + 1))/6. (End) If n>3 is prime, then a(n) == 1 (mod n). A generalization: if a_t(n) denote the number of permutations of n letters with exactly t descents (column t+1 of Euler's triangle A008292), then, for prime n>t, we have a(n) == 1 (mod n). - Vladimir Shevelev, Sep 26 2010 E.g.f.: exp(x)*(exp(3*x) - (1 + 3*x)*exp(2*x) + 2*(x + 2*x^2/2!)*exp(x) - x^2/2! - x^3/3!). - Wolfdieter Lang, Apr 17 2017 EXAMPLE There is one permutation of 4 with exactly 3 descents (4321). There are 26 permutations of 5 with 3 descents: 15432, 21543, 25431, 31542, 32154, 32541, 35421, 41532, 42153, 42531, 43152, 43215, 43251, 43521, 45321, 51432, 52143, 52431, 53142, 53214, 53241, 53421, 54132, 54213, 54231, 54312. - Neven Juric, Jan 21 2010. MAPLE A000498:=proc(n); 4^n-(n+1)*3^n+1/2*(n)*(n+1)*2^n-1/6*(n-1)*(n)*(n+1); end: MATHEMATICA LinearRecurrence[{20, -175, 882, -2835, 6072, -8777, 8458, -5204, 1848, -288}, {1, 26, 302, 2416, 15619, 88234, 455192, 2203488, 10187685, 45533450}, 30] (* Jean-François Alcover, Feb 09 2016 *) Table[(6*4^n - 6*(n + 1)*3^n + 3*(n)*(n + 1)*2^n - (n - 1)*(n)*(n + 1))/6, {n, 4, 50}] (* G. C. Greubel, Oct 23 2017 *) PROG (PARI) for(n=4, 50, print1((6*4^n - 6*(n + 1)*3^n + 3*(n)*(n + 1)*2^n - (n - 1)*(n)*(n + 1))/6, ", ")) \\ G. C. Greubel, Oct 23 2017 (MAGMA) [(6*4^n - 6*(n + 1)*3^n + 3*(n)*(n + 1)*2^n - (n - 1)*(n)*(n + 1))/6: n in [4..50]]; // 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. A066912. Sequence in context: A010831 A022718 A014472 * A066912 A015800 A276285 Adjacent sequences:  A000495 A000496 A000497 * A000499 A000500 A000501 KEYWORD nonn,nice,easy AUTHOR EXTENSIONS More terms from Christian G. Bower, May 12 2000 STATUS approved

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Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)