OFFSET
1,6
FORMULA
G.f.: Sum_{i>=1} Sum_{j>=1} q^(4*i+j)/Product_{k=i..3*i+j} (1-q^k).
EXAMPLE
a(7) = 4 counts these partitions: 61, 511, 421, 4111.
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 05 2026
STATUS
approved
