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A025283 Composites that use the same digits as their prime factorization. 15
25, 121, 1255, 2349, 5120, 12337, 12955, 17482, 25105, 41323, 43375, 93217, 100255, 101299, 105295, 107329, 117067, 124483, 127417, 129595, 132565, 145273, 146137, 149782, 163797, 174082, 174298, 174793, 174982, 191239, 250105, 256315, 263155 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Here exponents equal to 1 are not taken into account, so 1255 = 5^1*251^1 = 5*251 is a term. Prime numbers are excluded because they all trivially use the same digits as their prime factorization. If, on the contrary, exponents equal to 1 are counted, the resulting sequence is A075047. - Giovanni Resta, Jul 14 2015
An interesting example of the factorization digits appearing in the same order as in its composite generator: 13532385396179 = 13 * 53^2 * 3853 * 96179. - Hans Havermann, Jun 28 2017
LINKS
MATHEMATICA
Select[Range[10^5], !PrimeQ@ # && Sort@ IntegerDigits@ # == Sort@ Flatten@ IntegerDigits@ Select[ Flatten@ FactorInteger@ #, #>1 &] &] (* Giovanni Resta, Jul 14 2015 *)
CROSSREFS
Sequence in context: A198040 A141722 A090159 * A076433 A069668 A274785
KEYWORD
base,nonn
AUTHOR
STATUS
approved

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Last modified February 29 17:30 EST 2024. Contains 370428 sequences. (Running on oeis4.)