This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A075813 #10 Mar 10 2025 15:21:58 %S A075813 4,6,22,202,262,454,626,818,838,878,898,20302,20602,22322,22522,22622, %T A075813 22822,24142,24842,26662,26762,28682,41014,41414,41614,41714,43034, %U A075813 43234,43534,43634,45454,45554,45754,47074,47374,47774,49094,49394 %N A075813 Palindromic even numbers with exactly 2 prime factors (counted with multiplicity). Equivalently, palindromic numbers of the form 2*p with p prime. %e A075813 4=2^2, 6=2*3 and 22=2*11 are palindromic, even and have exactly 2 prime factors. %p A075813 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; %t A075813 Select[Range[50000],EvenQ[#]&&PalindromeQ[#]&&PrimeOmega[#]==2&] (* _Harvey P. Dale_, Oct 16 2024 *) %Y A075813 Cf. A001747. %Y A075813 Even subsequence of A046328. %K A075813 nonn,base %O A075813 1,1 %A A075813 _Jani Melik_, Oct 13 2002 %E A075813 Edited by _Dean Hickerson_, Oct 21 2002