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A046444 Composite numbers whose 4 prime factors are distinct in length. 1
2241998, 2250886, 2264218, 2268662, 2286394, 2290882, 2295326, 2295458, 2308658, 2309054, 2313586, 2330878, 2335322, 2336246, 2340778, 2354374, 2357542, 2361986, 2375186, 2375318, 2377034, 2381566, 2384602, 2398726 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Equivalently, the products of 4 prime numbers that have distinct lengths when written in decimal. - Peter Munn, May 30 2023
LINKS
EXAMPLE
2241998 because 2241998 = 2 * 11 * 101 * 1009, which have 1, 2, 3, and 4 digits, respectively.
MATHEMATICA
Select[Range[24*10^5], PrimeNu[#]==4&&Length[Union[IntegerLength/@ FactorInteger[ #][[All, 1]]]]==4&] (* Harvey P. Dale, Jan 12 2020 *)
CROSSREFS
Subsequence of A046386.
Sequence in context: A224628 A224629 A224636 * A349722 A180940 A089445
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jul 15 1998
STATUS
approved

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Last modified May 21 00:14 EDT 2024. Contains 372720 sequences. (Running on oeis4.)