OFFSET
1,2
COMMENTS
Multiplicative: If n = p^x * q^y * ... for distinct primes p,q,... then a(n) = a(p^x) * a(q^y) * ...
LINKS
David A. Corneth, PARI program.
FORMULA
a(n) | a(k*n), k=2,3,...
EXAMPLE
a(1) is trivially 1.
For n=2 the sequence is 0, {0,1,1}, {0,1,1}, hence a(2) = 3.
For n=3 the sequence is 0, {0,1,1,2}, {0,1,1,2}, hence a(3) = 4.
For n=4 the sequence is 0,0,1,1, {2,3,3}, {2,3,3}, hence a(4) = 3.
For n=5 the sequence is 0, {0,1,1,2,3,2,2}, {0,1,1,2,3,2,2}, hence a(5) = 7.
PROG
(PARI) See Corneth link \\ David A. Corneth, Sep 04 2020
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Isaac Kaufmann, Sep 03 2020
EXTENSIONS
More terms from Jinyuan Wang, Sep 04 2020
STATUS
approved