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!)
A167322 Totally multiplicative sequence with a(p) = 3*(p+3) for prime p. 1

%I #12 Oct 22 2023 00:51:22

%S 1,15,18,225,24,270,30,3375,324,360,42,4050,48,450,432,50625,60,4860,

%T 66,5400,540,630,78,60750,576,720,5832,6750,96,6480,102,759375,756,

%U 900,720,72900,120,990,864,81000,132,8100,138,9450,7776,1170,150,911250,900

%N Totally multiplicative sequence with a(p) = 3*(p+3) for prime p.

%H G. C. Greubel, <a href="/A167322/b167322.txt">Table of n, a(n) for n = 1..1000</a>

%F Multiplicative with a(p^e) = (3*(p+3))^e. If n = Product p(k)^e(k) then a(n) = Product (3*(p(k)+3))^e(k).

%F a(n) = A165824(n) * A166591(n) = 3^bigomega(n) * A166591(n) = 3^A001222(n) * A166591(n).

%t a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 3)^fi[[All, 2]])); Table[a[n]*3^PrimeOmega[n], {n, 1, 100}] (* _G. C. Greubel_, Jun 09 2016 *)

%t f[p_, e_] := (3*(p+3))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Oct 22 2023 *)

%Y Cf. A001222, A165824, A166591.

%K nonn,easy,mult

%O 1,2

%A _Jaroslav Krizek_, Nov 01 2009

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 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)