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

Terms

a(0) =1a(1) =6a(2) =22a(3) =33a(4) =55a(5) =77a(6) =111a(7) =141a(8) =161a(9) =202a(10) =262a(11) =303a(12) =323a(13) =393a(14) =454a(15) =505a(16) =515a(17) =535a(18) =545a(19) =565a(20) =626a(21) =707a(22) =717a(23) =737a(24) =767a(25) =818a(26) =838a(27) =858a(28) =878a(29) =898