OFFSET
0,5
COMMENTS
a(n) is the number of partitions of n into parts 2, 4, 9, and 11. - Hoang Xuan Thanh, Oct 12 2025
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,1,0,1,0,-1,0,0,1,0,0,0,-2,0,0,0,1,0,0,-1,0,1,0,1,0,-1).
FORMULA
a(n) = floor((n^3+39*n^2+600*n+3600)/4752 - (n+11)*(n mod 2)/16 + ((7*n^3+9*n^2+9*n+10) mod 11)/11) - [(n mod 11)=3] + [(n mod 11)=4]. - Hoang Xuan Thanh, Oct 12 2025
MATHEMATICA
CoefficientList[Series[1/((1-x^2)(1-x^4)(1-x^9)(1-x^11)), {x, 0, 80}], x] (* Harvey P. Dale, Nov 26 2014 *)
PROG
(PARI) Vec(1/((1-x^2)*(1-x^4)*(1-x^9)*(1-x^11)) + O(x^80)) \\ Jinyuan Wang, Mar 15 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved
