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A306474
Composite numbers that are anagrams of the concatenation of their prime factors.
1
735, 1255, 3792, 7236, 11913, 12955, 13175, 17276, 17482, 19075, 19276, 23535, 25105, 32104, 34112, 37359, 42175, 100255, 101299, 104392, 105295, 107329, 117067, 117873, 121325, 121904, 121932, 123544, 123678, 124483, 127417, 129595, 131832, 132565, 139925
OFFSET
1,1
COMMENTS
The sequence contains two subsequences:
Subsequence 1: numbers with distinct digits. This finite subsequence begins with the numbers 735, 3792, 7236, 17482, 19075, 19276, 32104, ...
Subsequence 2: numbers with non-distinct digits. This subsequence begins with the numbers 1255, 11913, 12955, 13175, 17276, 23535, ...
LINKS
EXAMPLE
3792 is in the sequence because the concatenation of the prime distinct divisors {2, 3, 79} is 2379, anagram of 3792.
MAPLE
with(numtheory):
for n from 1 to 140000 do:
if type(n, prime)=false
then
x:=factorset(n):n1:=nops(x): s:=0:s0:=0:
for i from n1 by -1 to 1 do:
a:=x[i]:b:=length(a):s:=s+a*10^s0:s0:=s0+b:
od:
if sort(convert(n, base, 10)) = sort(convert(s, base, 10))
then
printf(`%d, `, n):
else
fi:fi:
od:
MATHEMATICA
Select[Range[2, 140000], If [!PrimeQ[#], Sort@IntegerDigits@#==Sort[Join@@IntegerDigits[First/@FactorInteger[#]]]]&]
CROSSREFS
A121342 is a subsequence.
Sequence in context: A126556 A349870 A174456 * A250053 A227755 A096595
KEYWORD
nonn,base
AUTHOR
Michel Lagneau, Feb 18 2019
STATUS
approved