OFFSET
0,15
COMMENTS
Number of partitions of n into parts 4, 7, and 10. - Hoang Xuan Thanh, Sep 10 2025
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1,0,0,1,0,0,1,-1,0,0,-1,0,0,-1,0,0,0,1).
FORMULA
a(n) = a(n-4)+a(n-7)+a(n-10)-a(n-11)-a(n-14)-a(n-17)+a(n-21) with a(0)=1, a(1)=0, a(2)=0, a(3)=0, a(4)=1, a(5)=0, a(6)=0, a(7)=1, a(8)=1, a(9)=0, a(10)=1, a(11)=1, a(12)=1, a(13)=0, a(14)=2, a(15)=1, a(16)=1, a(17)=1, a(18)=2, a(19)=1, a(20)=2. - Harvey P. Dale, May 07 2014
a(n) = floor((n^2 + 21*n + 122)/560 + (n+10)*(-1)^n/80 + ((2*n^2+6) mod 7)/7). - Hoang Xuan Thanh, Sep 10 2025
MATHEMATICA
CoefficientList[Series[1/((1-x^4)(1-x^7)(1-x^10)), {x, 0, 90}], x] S(* or *)
LinearRecurrence[{0, 0, 0, 1, 0, 0, 1, 0, 0, 1, -1, 0, 0, -1, 0, 0, -1, 0, 0, 0, 1}, {1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 2, 1, 1, 1, 2, 1, 2}, 90] (* Harvey P. Dale, May 07 2014 *)
PROG
(PARI) a(n)=(n^2+21*n+122 + 7*(n+10)*(-1)^n + 80*((2*n^2+6)%7))\560 \\ Hoang Xuan Thanh, Sep 10 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved
