A013984 Expansion of 1/(1-x^2-x^3-x^4-x^5-x^6-x^7).

1, 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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Number of compositions of n into parts p where 2 <= p < = 7. [Joerg Arndt, Jun 24 2013]

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,1,1,1,1,1,1)

Programs

Magma

m:=40; R:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-x^2-x^3-x^4-x^5-x^6-x^7))); // Vincenzo Librandi, Jun 24 2013

Mathematica

CoefficientList[Series[1 / (1 - x^2 - x^3 - x^4 - x^5 - x^6 - x^7), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 23 2013 *)

PARI

Vec(1/(1-x^2-x^3-x^4-x^5-x^6-x^7)+O(x^99)) \\ Charles R Greathouse IV, Sep 25 2012