Search: id:A120419 Results 1-1 of 1 results found. %I A120419 %S A120419 1,2,22,584,28384,2190128,245762848,37788392576,7625538720256, %T A120419 1954588198280192,620259836756837632,238698984906300222464 %N A120419 A mysterious sequence. %C A120419 This is based on the derivatives of the real function g(x) := -1/f(x)^2. They have been generated using the software Mathematica. I'm trying to find a closed form. %C A120419 I have the complete program code and can send it to anyone interested. %D A120419 H. Sussmann, Resultats recents sur les courbes optimales, Soc. Math. de France du 17 juin 2000 %D A120419 H. Sussmann and J. C. Willems, 300 Years of Optimal Control - IEEE Control Systems 1997 0272-1708l97l$10.0001997IEEE %D A120419 H. Sussmann and J. C. Willems, The Brachistochrone Problem and Modern Control Theory - University of Groningen, May 1999 %H A120419 Eric Weisstein's World of Mathematics, http://mathworld.wolfram.com/UmbralCalculus.html %H A120419 Eric Weisstein's World of Mathematics, http://mathworld.wolfram.com/GeneratingFunction.html %H A120419 Eric Weisstein's World of Mathematics, http://mathworld.wolfram.com/CauchyProduct.html %F A120419 The algorithm for the sequence is as follows: (step#) What to do (1) Dj = 0, for each j, when j is odd (j=2k+1); (odd derivatives are null) (3) D2 = -1*f(a)^-2; then b1 = 1; (the 2nd derivative) (4) D4 = -2*f(a)^-5; (the 4th derivative) So b2 = 2; (5) D6 = -22*f(a)^-8; (the 6th derivative) So b3 = 22; (6) D8 = -584*f(a)^-11 (the 8th derivative) So b4 = 584; (8) D10= -28384*f(a)^-14 (the 10th derivative) So b5 = 28384; and so on... (n) D2n= -bn*f(a)^-(3n-1) (the 2n-th derivative) on general bn is unknown. %Y A120419 Sequence in context: A090730 A090313 A110129 this_sequence A132568 A015210 A152558 %Y A120419 Adjacent sequences: A120416 A120417 A120418 this_sequence A120420 A120421 A120422 %K A120419 uned,nonn,obsc,more %O A120419 0,2 %A A120419 Robert Wackensack (wackensack(AT)hotmail.com), Jul 09 2006 Search completed in 0.001 seconds