login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A325509 Number of factorizations of n! into factorial numbers > 1. 7

%I

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

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

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

%N Number of factorizations of n! into factorial numbers > 1.

%F a(n) = 1 + A034876(n).

%e n = 10:

%e (6*120*5040)

%e (720*5040)

%e (3628800)

%e n = 16:

%e (2*2*2*2*1307674368000)

%e (2*120*87178291200)

%e (20922789888000)

%e n = 24:

%e (2*2*6*25852016738884976640000)

%e (24*25852016738884976640000)

%e (620448401733239439360000)

%t facs[n_,u_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[facs[n/d,u],Min@@#>=d&]],{d,Intersection[u,Rest[Divisors[n]]]}]];

%t Table[Length[facs[n!,Rest[Array[#!&,n]]]],{n,15}]

%Y Cf. A000142, A011371, A022559, A034876, A034878, A076934, A109100, A109101, A109102, A115627, A135291, A322583, A325272, A325273, A325276, A325508, A325510, A325511.

%K nonn

%O 0,5

%A _Gus Wiseman_, May 08 2019

%E More terms from _Alois P. Heinz_, May 08 2019

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 September 17 19:02 EDT 2019. Contains 327137 sequences. (Running on oeis4.)