A075812 Palindromic odd numbers with exactly 2 prime factors (counted with multiplicity).

9, 33, 55, 77, 111, 121, 141, 161, 303, 323, 393, 505, 515, 535, 545, 565, 707, 717, 737, 767, 939, 949, 959, 979, 989, 1111, 1441, 1661, 1991, 3113, 3223, 3443, 3883, 7117, 7447, 7997, 9119, 9229, 9449, 10001, 10201, 10401, 10801, 10901, 11111

Offset: 1

Author

Jani Melik, Oct 13 2002

Keywords

• nonn
• base

Examples

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

Links

• Zak Seidov, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A046315.

Odd subsequence of A046328.

Programs

Maple

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;

Extensions

Edited by Dean Hickerson, Oct 21 2002