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A046393 Palindromes with exactly 3 distinct prime factors. 2

%I

%S 66,222,282,434,474,494,555,595,606,646,777,969,1001,1221,1551,1771,

%T 2222,2882,3333,3553,4334,4994,5335,5555,5665,5885,5995,6226,6446,

%U 6886,7337,7557,7667,7777,7887,8338,8558,8998,9339,9669,9779,9889,11211

%N Palindromes with exactly 3 distinct prime factors.

%C The terms must have only three distinct prime factors even when counted with multiplicity. For example, 252 is not a term even though (1) it is a palindrome and (2) only three distinct primes occur when it is factored, because 252 = 2*2*3*3*7. - _Harvey P. Dale_, Aug 29 2016

%H Chai Wah Wu, <a href="/A046393/b046393.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[12000],#==IntegerReverse[#]&&PrimeNu[#]==PrimeOmega[#]==3&] (* _Harvey P. Dale_, Aug 29 2016 *)

%Y Cf. A046329, A046409.

%K nonn,base

%O 1,1

%A _Patrick De Geest_, Jun 15 1998

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Last modified August 9 21:08 EDT 2022. Contains 356026 sequences. (Running on oeis4.)