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!)
A083182 Greatest 3-brilliant number of size n. 1
8, 98, 343, 9971, 99937, 912673, 9999707, 99999667, 991026973, 9999999467, 99999999007, 991921850317, 9999999994771, 99999999994117, 999730024299271, 9999999999997097, 99999999999992023, 999949000866995087 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Brilliant numbers, as defined by Peter Wallrodt, are numbers with two prime factors of the same length (in decimal notation). These numbers are generally used for cryptographic purposes and for testing the performance of prime factoring programs.

a(3n) will always be the cube of the greatest prime less than 10^n.

LINKS

Table of n, a(n) for n=1..18.

Dario Alpern, Brilliant numbers

EXAMPLE

a(5) = 99937 = 37 * 37 * 73 and there is no greater number of five digits which has three prime factors, not necessarily different, of the same size in decimal notation.

CROSSREFS

Cf. A083128.

Sequence in context: A218451 A262777 A292747 * A302277 A302727 A116267

Adjacent sequences:  A083179 A083180 A083181 * A083183 A083184 A083185

KEYWORD

nonn,base

AUTHOR

Robert G. Wilson v, May 11 2003

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 August 11 22:58 EDT 2022. Contains 356067 sequences. (Running on oeis4.)