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A046442 Semiprimes whose two prime factors are distinct in length. 1
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
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
Equals A001358 \ A078972.
Sequence in context: A084891 A162422 A063940 * A101549 A277624 A243140
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jul 15 1998
STATUS
approved

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Last modified February 22 22:43 EST 2024. Contains 370265 sequences. (Running on oeis4.)