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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A336651 Odd part of n divided by its largest squarefree divisor. 9
 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 5, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 7, 5, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 5, 1, 1, 1, 1, 1, 27, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 7, 3, 5, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,9 COMMENTS The name can be parsed either as "Odd part of {n divided by its largest squarefree divisor}" or "Odd part of n, divided by its largest squarefree divisor". Because A000265 and A003557 commute, both interpretations yield equal results. LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA Multiplicative with a(2^e) = 1, and for odd primes p, a(p^e) = p^(e-1). a(n) = A003557(A000265(n)) = A000265(A003557(n)). a(n) = A000265(n) / A204455(n). A000203(a(n)) = A336649(n). Dirichlet g.f.: (1 - 1/(2^s-1)^2) * zeta(s-1) * Product_{p prime} (1 - 1/p^(s-1) + 1/p^s). - Amiram Eldar, Sep 14 2023 MATHEMATICA f[2, e_] := 1; f[p_, e_] := p^(e-1); a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Dec 07 2020 *) PROG (PARI) A336651(n) = { my(f=factor(n)); prod(i=1, #f~, if(2==f[i, 1], 1, f[i, 1]^(f[i, 2]-1))); }; CROSSREFS Cf. A000203, A000265, A003557, A007947, A336649, A336652. Sequence in context: A030576 A101874 A318449 * A066715 A082457 A356307 Adjacent sequences: A336648 A336649 A336650 * A336652 A336653 A336654 KEYWORD nonn,easy,mult AUTHOR Antti Karttunen, Jul 30 2020 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.

Last modified November 29 07:03 EST 2023. Contains 367429 sequences. (Running on oeis4.)