OFFSET
1,1
COMMENTS
Smallest value where each factor has n digits for n = 1, 2, 3, 4, 5, are: 6 = 2 * 3; 253 = 11 * 23; 25651 = 113 * 227; 2035153 = 1009 * 2017; 202457503 = 10061 * 20123. [From Jonathan Vos Post, Apr 04 2009]
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
253 = T(22) and 253 = 11*23 is brilliant.
MATHEMATICA
brilQ[n_]:=Module[{fin=FactorInteger[n]}, Total[Transpose[fin][[2]]]==2&& Length[Union[IntegerLength[Transpose[fin][[1]]]]]==1]
Intersection[Accumulate[Range[850]], Select[Range[362000], brilQ]] (* Harvey P. Dale, Feb 06 2011 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Giovanni Resta, Jan 31 2006
STATUS
approved