Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A097655
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
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. +0
6
1, 2, 3, 15, 18432, 75600, 276531978240000, 4810168001497883738112000, 215788176336727572480000000, 2178419737991700039289327133392896000000000000 (list; graph; listen)
OFFSET

1,2

COMMENT

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

EXAMPLE

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

MATHEMATICA

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

CROSSREFS

Cf. A097653, A097654, A097643, A102279.

Adjacent sequences: A097652 A097653 A097654 this_sequence A097656 A097657 A097658

Sequence in context: A091835 A131612 A087975 this_sequence A080749 A070973 A054496

KEYWORD

base,nonn

AUTHOR

Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Sep 10 2004

EXTENSIONS

More terms from Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Jan 08 2005

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified October 13 09:05 EDT 2008. Contains 145008 sequences.


AT&T Labs Research