A046442 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A046442

Semiprimes whose two prime factors are distinct in length.

22, 26, 33, 34, 38, 39, 46, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 106, 111, 115, 118, 119, 122, 123, 129, 133, 134, 141, 142, 145, 146, 155, 158, 159, 161, 166, 177, 178, 183, 185, 194, 201, 202, 203, 205, 206, 213, 214, 215, 217

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Semiprimes (A001358) that are not brilliant numbers (A078972). - Bernard Schott, Jul 29 2022

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

203 because 203 = 7 * 29, which have 1 and 2 digits, respectively.

MATHEMATICA

Take[Union[Times@@@Select[Subsets[Prime[Range[50]], {2}], IntegerLength[#[[1]]]!=IntegerLength[#[[2]]]&]], 60] (* Harvey P. Dale, Dec 29 2010 *)

CROSSREFS