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!)
A114571 a(n) is the smallest value k for which k!! >= n!. 0

%I

%S 1,2,4,6,8,9,11,12,14,16,18,19,21,23,24,26,28,30,31,33,35,36,38,40,42,

%T 43,45,47,48,50,52,54,55,57,59,61,62,64,66,68,69,71,73,75,76,78,80,82,

%U 84,85,87,89,91,92,94,96,98,99,101,103,105,106,108,110,112,114,115,117

%N a(n) is the smallest value k for which k!! >= n!.

%e a(6)=9 since m!!<6! for m<9, while 9!!>=6!.

%t Module[{df=Table[{i,i!!},{i,200}]},Transpose[Table[SelectFirst[df, #[[2]]>= n!&],{n,100}]][[1]]] (* _Harvey P. Dale_, Nov 05 2015 *)

%K easy,nonn

%O 1,2

%A _Giovanni Resta_, Feb 16 2006

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 May 23 10:51 EDT 2022. Contains 353975 sequences. (Running on oeis4.)