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Palindromic odd numbers with exactly 2 prime factors (counted with multiplicity).
1

%I #11 Jun 24 2014 01:08:26

%S 9,33,55,77,111,121,141,161,303,323,393,505,515,535,545,565,707,717,

%T 737,767,939,949,959,979,989,1111,1441,1661,1991,3113,3223,3443,3883,

%U 7117,7447,7997,9119,9229,9449,10001,10201,10401,10801,10901,11111

%N Palindromic odd numbers with exactly 2 prime factors (counted with multiplicity).

%C Odd subsequence of A046328 Palindromes with exactly 2 prime factors (counted with multiplicity). - Zak Seidov, Feb 20 2011

%H Zak Seidov, <a href="/A075812/b075812.txt">Table of n, a(n) for n = 1..2000</a>

%e 9=3^2, 33=3*11 and 55=5*11 are palindromic, odd and are products of exactly 2 prime factors.

%p test := proc(n) local d; d := convert(n,base,10); return ListTools[Reverse](d)=d and numtheory[bigomega](n)=2; end; a := []; for n from 1 to 14000 by 2 do if test(n) then a := [op(a),n]; end; od; a;

%Y Cf. A046328, A046315.

%K nonn,base

%O 1,1

%A _Jani Melik_, Oct 13 2002

%E Edited by _Dean Hickerson_, Oct 21 2002