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

1,1

Comments

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

Links

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

Example

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

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;

Crossrefs

Cf. A046328, A046315.

Sequence in context: A111351 A065064 A337234 * A256868 A146262 A161430

Adjacent sequences: A075809 A075810 A075811 * A075813 A075814 A075815

Keyword

nonn,base

Author

Jani Melik, Oct 13 2002

Extensions

Edited by Dean Hickerson, Oct 21 2002

Status

approved