login
A075799
Palindromic numbers which are products of an even number of distinct primes.
0
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
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
KEYWORD
nonn,base
AUTHOR
Jani Melik, Oct 13 2002
EXTENSIONS
Edited by Dean Hickerson, Oct 21 2002
STATUS
approved