A107479 a(n) = a(n-2) + a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7).

0, 1, 1, 2, 3, 5, 8, 12, 20, 31, 50, 79, 126, 200, 318, 506, 804, 1279, 2033, 3233, 5140, 8173, 12995, 20662, 32853, 52236, 83056, 132059, 209975, 333861, 530841, 844040, 1342028, 2133832, 3392804, 5394577, 8577406, 13638122, 21684687, 34478769

Offset: 0

Author

Roger L. Bagula, May 27 2005

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Peter Borwein and Kevin G. Hare, Some computations on Pisot and Salem numbers, 2000, table 1, p. 7.
• Index entries for linear recurrences with constant coefficients, signature (0,1,1,1,1,1,1).

Crossrefs

Cf. A013984.

Cf. A107480, A109538, A109543, A109544, A114749, A125950, A130844, A143335, A147851.

Programs

Magma

m:=50; R:=PowerSeriesRing(Integers(), m); [0] cat Coefficients(R!(x*(1+x)*(1+x+x^2)*(x^2-x+1)/(1-x^2-x^3-x^4-x^5-x^6-x^7) )); // G. C. Greubel, Nov 03 2018

Mathematica

LinearRecurrence[{0,1,1,1,1,1,1}, {0,1,1,2,3,5,8}, 40] (* Harvey P. Dale, Sep 26 2012 *)
CoefficientList[Series[x (1 + x) (1 + x + x^2) (x^2 - x + 1)/(1 - x^2 - x^3 - x^4 - x^5 - x^6 - x^7), {x, 0, 40}], x] (* Vincenzo Librandi, Oct 16 2014 *)

PARI

concat(0, Vec(x*(1+x)*(1+x+x^2)*(x^2-x+1)/(1-x^2-x^3-x^4-x^5-x^6-x^7) + O(x^60))) \\ Michel Marcus, Oct 16 2014

Formula

Lim_{n->infinity} a(n)/a(n-1) = 1.5900053739...

G.f.: x*(1 + x)*(1 - x + x^2)*(1 + x + x^2)/(1 - x^2 - x^3 - x^4 - x^5 - x^6 - x^7).

Extensions

Definition replaced by recurrence - The Associate Editors of the OEIS, Oct 02 2009

Spelling and formatting corrected, index link added - Charles R Greathouse IV, Jan 26 2011