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A083182
Greatest 3-brilliant number of size n.
3
8, 98, 343, 9971, 99937, 912673, 9999707, 99999667, 991026973, 9999999467, 99999999007, 991921850317, 9999999994771, 99999999994117, 999730024299271, 9999999999997097, 99999999999992023, 999949000866995087
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.
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: A367493 A365845 A292747 * A302277 A302727 A116267
KEYWORD
nonn,base
AUTHOR
Robert G. Wilson v, May 11 2003
STATUS
approved