OFFSET
0,7
COMMENTS
Number of compositions of n into parts p where 3 <= p <= 11. [Joerg Arndt, Jun 27 2013]
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,1,1,1,1,1,1,1,1,1).
FORMULA
a(0)=1, a(1)=0, a(2)=0, a(3)=1, a(4)=1, a(5)=1, a(6)=2, a(7)=3, a(8)=4, a(9)=6, a(10)=9; for n>10, a(n) = a(n-3) +a(n-4) +a(n-5) +a(n-6) +a(n-7) +a(n-8) +a(n-9) +a(n-10) +a(n-11). - Harvey P. Dale, Sep 07 2012
MATHEMATICA
CoefficientList[Series[1/(1 - Total[x^Range[3, 11]]), {x, 0, 40}], x] (* or *) LinearRecurrence[ {0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 0, 0, 1, 1, 1, 2, 3, 4, 6, 9}, 41] (* Harvey P. Dale, Sep 07 2012 *)
PROG
(Magma) m:=50; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-x^3-x^4-x^5-x^6-x^7-x^8-x^9-x^10-x^11))); /* or */ I:=[1, 0, 0, 1, 1, 1, 2, 3, 4, 6, 9]; [n le 11 select I[n] else Self(n-3)+Self(n-4)+Self(n-5)+Self(n-6)+Self(n-7)+Self(n-8)+Self(n-9)+Self(n-10)+Self(n-11): n in [1..50]]; // Vincenzo Librandi, Jun 27 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved