OFFSET
0,9
FORMULA
a(n) = A060763(n!).
EXAMPLE
For n up to 7 all divisor differences of n! are also divisors of n!.
For n = 8, there are 3 divisor differences of 8! = 40320 which are not divisors of 8!, namely 27, 54 and 108.
MATHEMATICA
a[n_ ] := Length[Complement[Drop[d=Divisors[n! ], 1]-Drop[d, -1], d]]
PROG
(PARI) a(n) = {my(v = List(), f = n!, d1 = 1, del); fordiv(f, d, if(d > 1, del = d - d1; if(f % del, listput(v, del)); d1 = d)); #Set(v); } \\ Amiram Eldar, Jun 15 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 25 2001
EXTENSIONS
Edited by Dean Hickerson, Jan 22 2002
More terms from Sean A. Irvine, Dec 21 2022
a(41) from Amiram Eldar, Jun 15 2024
STATUS
approved