OFFSET
1
COMMENTS
Conjectures:
1) The only distinct terms of this sequence are -1, 0 and 1.
2) The asymptotic density of the occurrences of 0 is 0.943..., and the asymptotic densities of the occurrences of -1 and 1 are equal and the common value is 0.028... .
These conjectures are empirically supported by the following numbers of occurrences of the terms -1, 0 and 1 up to n = 10^k:
k -1 0 1
- ------- ------- ------
1 0 6 4
2 1 87 12
3 28 913 59
4 362 9189 449
5 3159 93430 3411
6 27853 943571 28576
7 281802 9434309 283889
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(p) = 0 for an odd prime p.
MATHEMATICA
s[n_] := Length[Union[FactorInteger[n!][[;; , 2]]]]; s[1] = 0; Differences[Table[s[n], {n, 1, 100}]]
CROSSREFS
KEYWORD
sign
AUTHOR
Amiram Eldar, Sep 26 2022
STATUS
approved