Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A050677
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A050677 Number of prime factors of concatenation of numbers from n down to 1, with multiplicity. +0
9
1, 2, 2, 2, 3, 2, 2, 4, 5, 3, 2, 3, 3, 4, 6, 4, 7, 10, 4, 5, 4, 5, 4, 5, 6, 9, 9, 5, 7, 8, 3, 6, 5, 7, 9, 8, 4, 3, 6, 5, 8, 6, 3, 8, 7, 5, 7, 7, 3, 6, 3, 7, 12, 14, 3, 5, 4, 6, 3, 3, 5, 9, 6, 6 (list; graph; listen)
OFFSET

1,2

COMMENT

Strictly speaking a(1) = 0.

Smallest number not yet factored is 656463...4321.

REFERENCES

M. Fleuren, Smarandache Factors and Reverse Factors, Smarandache Notions Journal, 10 (No. 1-2-3, Spring 1999), 5-38.

LINKS

P. De Geest, Reversed Smarandache Concatenated Numbers, Prime factors from n down to 1

M. L. Perez et al., eds., Smarandache Notions Journal

C. Rivera, Primes by Listing

M. Fleuren, Factors and primes of Smarandache sequences.

M. Fleuren, Smarandache Factors and Reverse factors

EXAMPLE

21 = 3*7 so a(2) = 2; 321 = 3*107 so a(3) =2; 4321 = 29*149 so a(4) = 2; etc.

CROSSREFS

Cf. A000422, A046460, A050679-A050682.

Sequence in context: A099774 A142240 A048288 this_sequence A058013 A031356 A024676

Adjacent sequences: A050674 A050675 A050676 this_sequence A050678 A050679 A050680

KEYWORD

nonn,base,hard

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com), Aug 15 1999.

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 November 25 20:09 EST 2009. Contains 167514 sequences.


AT&T Labs Research