The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A100683 a(n) = a(n-1) + a(n-2) + a(n-3); a(0) = -1, a(1) = 2, a(2) = 2. 53
 -1, 2, 2, 3, 7, 12, 22, 41, 75, 138, 254, 467, 859, 1580, 2906, 5345, 9831, 18082, 33258, 61171, 112511, 206940, 380622, 700073, 1287635, 2368330, 4356038, 8012003, 14736371, 27104412, 49852786, 91693569, 168650767, 310197122 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS A tribonacci sequence. LINKS Robert Price, Table of n, a(n) for n = 0..1000 Martin Burtscher, Igor Szczyrba, RafaĆ Szczyrba, Analytic Representations of the n-anacci Constants and Generalizations Thereof, Journal of Integer Sequences, Vol. 18 (2015), Article 15.4.5. S. Kak, The Golden Mean and the Physics of Aesthetics, arXiv:physics/0411195 [physics.hist-ph], 2004. Eric Weisstein's World of Mathematics, Tribonacci Number Index entries for linear recurrences with constant coefficients, signature (1,1,1). FORMULA a(n+1) = 2*A001590(n+1) + A020992(n). - Creighton Dement, May 02 2005 O.g.f.: -(1-3x-x^2)/(1-x-x^2-x^3). - R. J. Mathar, Aug 22 2008 MAPLE a[0]:=-1:a[1]:=2:a[2]:=2:for n from 3 to 42 do a[n]:=a[n-1]+a[n-2]+a[n-3] od: seq(a[n], n=0..42); MATHEMATICA a[0] = -1; a[1] = a[2] = 2; a[n_] := a[n] = a[n - 1] + a[n - 2] + a[n - 3]; Table[ a[n], {n, 0, 35}] (* Robert G. Wilson v, Dec 09 2004 *) LinearRecurrence[{1, 1, 1}, {-1, 2, 2}, 34] (* Ray Chandler, Dec 08 2013 *) PROG (PARI) Vec(-(1-3*x-x^2)/(1-x-x^2-x^3) + O(x^70)) \\ Michel Marcus, Sep 25 2015 CROSSREFS Cf. A232542, A232543. Sequence in context: A179283 A234850 A127165 * A153940 A049905 A167348 Adjacent sequences:  A100680 A100681 A100682 * A100684 A100685 A100686 KEYWORD sign,easy AUTHOR N. J. A. Sloane, Dec 08 2004 EXTENSIONS More terms from Emeric Deutsch, Farideh Firoozbakht and Robert G. Wilson v, Dec 08 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 21 05:39 EST 2020. Contains 331104 sequences. (Running on oeis4.)