The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A097655 Numbers n such that n = d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of n. 6

%I #8 Dec 22 2014 14:55:09

%S 1,2,3,15,18432,75600,276531978240000,4810168001497883738112000,

%T 215788176336727572480000000,

%U 2178419737991700039289327133392896000000000000

%N Numbers n such that n = d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of n.

%C All terms are of the form 2^i*3^j*5^k*7^l.

%e 18432 is in the sequence because 18432 = 1!!*8!!*4!!*3!!*2!!.

%t Do[h=IntegerDigits[n];l=Length[h];If[n==Product[h[[k]]!!, {k, l}], Print[n]], {n, 2000000000}]

%Y Cf. A097653, A097654, A097643, A102279.

%K base,nonn

%O 1,2

%A _Farideh Firoozbakht_, Sep 10 2004

%E More terms from _Farideh Firoozbakht_, Jan 08 2005

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 June 8 04:51 EDT 2024. Contains 373207 sequences. (Running on oeis4.)