A075799 Palindromic numbers which are products of an even number of distinct primes.

1, 6, 22, 33, 55, 77, 111, 141, 161, 202, 262, 303, 323, 393, 454, 505, 515, 535, 545, 565, 626, 707, 717, 737, 767, 818, 838, 858, 878, 898, 939, 949, 959, 979, 989, 1111, 1441, 1661, 1991, 2002, 2442, 3003, 3113, 3223, 3443, 3883, 4774, 5005, 5115, 6666

Offset

1,2

Links

Table of n, a(n) for n=1..50.

Example

1, 111=3*37 and 858=2*3*11*13 are palindromic and products of an even number of distinct primes.

Maple

test := proc(n) local d; d := convert(n, base, 10); return ListTools[Reverse](d)=d and numtheory[mobius](n)=1; end; a := []; for n from 1 to 7000 do if test(n) then a := [op(a), n]; end; od; a;

Crossrefs

Cf. A046392, A002385, A069217, A032350, A030229.

Sequence in context: A015709 A020195 A035134 * A046392 A046408 A123017

Adjacent sequences: A075796 A075797 A075798 * A075800 A075801 A075802

Keyword

nonn,base

Author

Jani Melik, Oct 13 2002

Extensions

Edited by Dean Hickerson, Oct 21 2002

Status

approved