OFFSET
0,3
COMMENTS
Number of partitions of n into parts 1, 2, 3, and 7. [Joerg Arndt, Jul 06 2013]
LINKS
Index entries for linear recurrences with constant coefficients, signature (1, 1, 0, -1, -1, 1, 1, -1, -1, 0, 1, 1, -1).
FORMULA
a(n) = floor((n+12)*(2*n^2+15*n+42)/504). - Tani Akinari, Jul 06 2013
a(0)=1, a(1)=1, a(2)=2, a(3)=3, a(4)=4, a(5)=5, a(6)=7, a(7)=9, a(8)=11, a(9)=14, a(10)=17, a(11)=20, a(12)=24, a(n)=a(n-1)+a(n-2)-a(n-4)- a(n-5)+ a(n-6)+a(n-7)-a(n-8)-a(n-9)+a(n-11)+a(n-12)-a(n-13). - Harvey P. Dale, Nov 13 2013
MATHEMATICA
CoefficientList[Series[1/((1-x)(1-x^2)(1-x^3)(1-x^7)), {x, 0, 50}], x] (* or *) LinearRecurrence[{1, 1, 0, -1, -1, 1, 1, -1, -1, 0, 1, 1, -1}, {1, 1, 2, 3, 4, 5, 7, 9, 11, 14, 17, 20, 24}, 50] (* Harvey P. Dale, Nov 13 2013 *)
PROG
(PARI) Vec(1/((1-x)*(1-x^2)*(1-x^3)*(1-x^7))+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved