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!)
A076155 Omega(n) = Omega(n-1)^3, where Omega(m) (A001222) denotes the number of prime factors of m, counting multiplicity. 0

%I

%S 2,3,896,960,1344,1944,2160,2496,3240,3264,3600,3648,3712,3744,4416,

%T 4536,4736,4860,4928,5568,5600,5616,5952,6000,6240,6624,7290,7344,

%U 7392,7616,7808,7872,8160,8208,8352,8400,8512,8736,8928,9024,9120,9936

%N Omega(n) = Omega(n-1)^3, where Omega(m) (A001222) denotes the number of prime factors of m, counting multiplicity.

%e Omega(896) = 2^3 = Omega(895)^2, so 896 is a term of the sequence.

%t Omega[n_] := Apply[Plus, Transpose[FactorInteger[n]][[2]]]; l = {2}; Do[ If[Omega[i] == (Omega[i - 1])^3, l = Append[l, i]], {i, 3, 10^4}]; l

%t Join[{2},Flatten[Position[Partition[PrimeOmega[Range[10000]],2,1],_?(#[[1]]^3==#[[2]]&),1,Heads->False]]+1] (* _Harvey P. Dale_, Sep 22 2017 *)

%K easy,nonn

%O 1,1

%A _Joseph L. Pe_, Oct 31 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 August 4 06:02 EDT 2021. Contains 346442 sequences. (Running on oeis4.)