login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A329612 a(n) = gcd(d(n), d(A108951(n))), where d(n) gives the number of divisors of n, A000005(n), and A108951 is fully multiplicative with a(prime(i)) = prime(i)# = prime(1) * ... * prime(i). 3
1, 2, 2, 3, 2, 2, 2, 4, 3, 4, 2, 2, 2, 4, 2, 5, 2, 6, 2, 2, 4, 4, 2, 2, 3, 4, 4, 2, 2, 8, 2, 6, 4, 4, 2, 3, 2, 4, 4, 4, 2, 8, 2, 2, 2, 4, 2, 2, 3, 6, 4, 2, 2, 4, 4, 8, 4, 4, 2, 6, 2, 4, 2, 7, 4, 8, 2, 2, 4, 8, 2, 6, 2, 4, 6, 2, 2, 8, 2, 2, 5, 4, 2, 12, 4, 4, 4, 8, 2, 4, 4, 2, 4, 4, 4, 2, 2, 6, 2, 9, 2, 8, 2, 8, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = gcd(A000005(n),A329605(n)) = gcd(A000005(n),A000005(A108951(n))).
PROG
(PARI)
A034386(n) = prod(i=1, primepi(n), prime(i));
A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A034386(f[i, 1])^f[i, 2]) }; \\ From A108951
A329612(n) = gcd(numdiv(n), numdiv(A108951(n)));
CROSSREFS
Sequence in context: A328401 A207666 A151613 * A305980 A329601 A230578
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 18 2019
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)