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 A022816 Number of terms in 6th derivative of a function composed with itself n times. 4
 1, 11, 44, 121, 271, 532, 952, 1590, 2517, 3817, 5588, 7943, 11011, 14938, 19888, 26044, 33609, 42807, 53884, 67109, 82775, 101200, 122728, 147730, 176605, 209781, 247716, 290899, 339851, 395126, 457312, 527032, 604945, 691747 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES W. C. Yang (yang(AT)math.wisc.edu), Derivatives of self-compositions of functions, preprint, 1997. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..10000 W. C. Yang, Derivatives are essentially integer partitions, Discrete Mathematics, 222(1-3), July 2000, 235-245. Index entries for linear recurrences with constant coefficients, signature (6, -15, 20, -15, 6, -1). FORMULA a(n) = n*(n+1)*(n^3+24*n^2+81*n-46)/120. G.f.: x*(1+5*x-7*x^2+2*x^3)/(x-1)^6. - R. J. Mathar, Sep 15 2009 MATHEMATICA Table[n(n+1)(n^3+24n^2+81n-46)/120, {n, 40}] (* or *) LinearRecurrence[{6, -15, 20, -15, 6, -1}, {1, 11, 44, 121, 271, 532}, 40] (* Harvey P. Dale, Dec 29 2017 *) PROG (MAGMA) [n*(n+1)*(n^3+24*n^2+81*n-46)/120: n in [1..40]]; // Vincenzo Librandi, Oct 10 2011 CROSSREFS Cf. A008778, A022811-A022818, A024207-A024210. Sequence in context: A111080 A299288 A299286 * A120537 A068596 A002089 Adjacent sequences:  A022813 A022814 A022815 * A022817 A022818 A022819 KEYWORD nonn AUTHOR EXTENSIONS More terms from Christian G. Bower, Aug 15 1999. STATUS approved

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Last modified November 18 14:59 EST 2019. Contains 329262 sequences. (Running on oeis4.)