login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A072047 Number of prime factors of the squarefree numbers: omega(A005117(n)). 15

%I

%S 0,1,1,1,2,1,2,1,1,2,2,1,1,2,2,1,2,1,3,1,2,2,2,1,2,2,1,3,1,2,1,2,1,2,

%T 2,2,1,1,2,2,3,1,2,3,1,1,2,2,3,1,2,1,2,2,2,1,2,2,2,2,1,1,3,1,3,2,1,1,

%U 3,2,1,3,2,2,2,2,2,1,2,3,1,2,2,1,3,1,2

%N Number of prime factors of the squarefree numbers: omega(A005117(n)).

%C a(n) = A001221(A005117(n)) = A001222(A005117(n)).

%C For n > 1: length of row n in A265668. - _Reinhard Zumkeller_, Dec 13 2015

%H Reinhard Zumkeller, <a href="/A072047/b072047.txt">Table of n, a(n) for n = 1..10000</a>

%t PrimeOmega[Select[Range[200],SquareFreeQ]] (* _Harvey P. Dale_, May 14 2011 *)

%o (Haskell)

%o a072047 n = a072047_list !! (n-1)

%o a072047_list = map a001221 $ a005117_list

%o -- _Reinhard Zumkeller_, Aug 08 2011

%Y Cf. A072048.

%Y Cf. A001221, A001222, A005117, A265668.

%K nonn,nice

%O 1,5

%A _Reinhard Zumkeller_, Jun 09 2002

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 18 00:43 EDT 2021. Contains 343992 sequences. (Running on oeis4.)