OFFSET
0,13
COMMENTS
Number of partitions of n into parts 4, 5, and 12. - Hoang Xuan Thanh, Sep 09 2025
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1,1,0,0,0,-1,0,0,1,0,0,0,-1,-1,0,0,0,1).
FORMULA
a(0)=1, a(1)=0, a(2)=0, a(3)=0, a(4)=1, a(5)=1, a(6)=0, a(7)=0, a(8)=1, a(9)=1, a(10)=1, a(11)=0, a(12)=2, a(13)=1, a(14)=1, a(15)=1, a(16)=2, a(17)=2, a(18)=1, a(19)=1, a(20)=3, a(n)=a(n-4)+a(n-5)-a(n-9)+ a(n-12)-a(n-16)- a(n-17)+a(n-21). - Harvey P. Dale, Mar 22 2015
a(n) = floor((n+12)*(n+24)/480 - n*(n mod 4)/48 + ((4*n^2+4*n+2) mod 5)/5). - Hoang Xuan Thanh, Sep 09 2025
MATHEMATICA
CoefficientList[Series[1/((1-x^4)(1-x^5)(1-x^12)), {x, 0, 100}], x] (* or *) LinearRecurrence[{0, 0, 0, 1, 1, 0, 0, 0, -1, 0, 0, 1, 0, 0, 0, -1, -1, 0, 0, 0, 1}, {1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 2, 1, 1, 1, 2, 2, 1, 1, 3}, 100] (* Harvey P. Dale, Mar 22 2015 *)
PROG
(PARI) a(n) = ((n+12)*(n+24) - 10*n*(n%4) + 96*((4*n^2+4*n+2)%5))\480 \\ Hoang Xuan Thanh, Sep 09 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved
