OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
Wikipedia, Factorial number system
FORMULA
G.f.: Product_{j>=1} Sum_{k=0..j+1} x^(k*j!) = Product_{j>=1} (1-x^((j+1)!+j!))/(1-x^(j!)).
EXAMPLE
a(6) = 3 because we have [6], [2,2,2] and [2,2,1,1].
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Seiichi Manyama, May 05 2018
STATUS
approved