A075813 - OEIS

%I #6 Jun 24 2014 01:08:26

%S 4,6,22,202,262,454,626,818,838,878,898,20302,20602,22322,22522,22622,

%T 22822,24142,24842,26662,26762,28682,41014,41414,41614,41714,43034,

%U 43234,43534,43634,45454,45554,45754,47074,47374,47774,49094,49394

%N Palindromic even numbers with exactly 2 prime factors (counted with multiplicity). Equivalently, palindromic numbers of the form 2*p with p prime.

%e 4=2^2, 6=2*3 and 22=2*11 are palindromic, even and have exactly 2 prime factors.

%p 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 2 to 50000 by 2 do if test(n) then a := [op(a),n]; end; od; a;

%Y Cf. A001747.

%K nonn,base

%O 1,1

%A _Jani Melik_, Oct 13 2002

%E Edited by _Dean Hickerson_, Oct 21 2002