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!)
A106662 Smallest semiprime ending in exactly n 7's. 0
57, 77, 3777, 17777, 277777, 1777777, 17777777, 877777777, 3777777777, 17777777777, 577777777777, 1777777777777, 37777777777777, 877777777777777, 4777777777777777, 37777777777777777, 277777777777777777 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(3)=3777 is a term because 3777 is the smallest semiprime ending in exactly three 7's.
CROSSREFS
Sequence in context: A043252 A044032 A104760 * A087922 A087921 A196580
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, May 12 2005
STATUS
approved

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 March 19 01:57 EDT 2024. Contains 370952 sequences. (Running on oeis4.)