OFFSET
0,3
COMMENTS
Number of compositions of n into parts 1, 2, 6, 24, ..., k!, ...
The first terms are the same as for A120400, but the two sequences are different.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: 1/(1 - Sum_{k>=1} x^k! ).
MAPLE
a:= proc(n) option remember; local i, s; if n=0 then 1
else s:=0; for i while i!<=n do s:=s+a(n-i!) od; s fi
end:
seq(a(n), n=0..50); # Alois P. Heinz, Feb 14 2013
MATHEMATICA
nn=41; CoefficientList[Series[1/(1-Sum[x^(i!), {i, 1, 10}]), {x, 0, nn}], x] (* Geoffrey Critzer, Sep 29 2013 *)
PROG
(PARI)
N=66; x='x+O('x^N);
/* choose upper limit b in following sum such that b! > N */
Vec( 1/( 1 - sum(k=1, 7, x^(k!) ) ) )
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt, Sep 30 2012
STATUS
approved