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!)
A167341 Totally multiplicative sequence with a(p) = p*(p-3) = p^2-3p for prime p. 1
1, -2, 0, 4, 10, 0, 28, -8, 0, -20, 88, 0, 130, -56, 0, 16, 238, 0, 304, 40, 0, -176, 460, 0, 100, -260, 0, 112, 754, 0, 868, -32, 0, -476, 280, 0, 1258, -608, 0, -80, 1558, 0, 1720, 352, 0, -920, 2068, 0, 784, -200 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
Multiplicative with a(p^e) = (p*(p-3))^e. If n = Product p(k)^e(k) then a(n) = Product (p(k)*(p(k)-3))^e(k).
a(3k) = 0 for k >= 1.
a(n) = n * A166589(n).
Sum_{k=1..n} a(k) ~ c * n^3, where c = (2/Pi^2) / Product_{p prime} (1 + 2/p^2 + 3/p^3) = 0.06544931251... . - Amiram Eldar, Dec 15 2022
MATHEMATICA
a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 3)^fi[[All, 2]])); Table[a[n]*n, {n, 1, 100}] (* G. C. Greubel, Jun 10 2016 *)
CROSSREFS
Cf. A166589.
Sequence in context: A111938 A224822 A246928 * A359188 A361269 A343472
KEYWORD
sign,mult
AUTHOR
Jaroslav Krizek, Nov 01 2009
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 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)