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 A075800 #16 Mar 10 2025 09:42:16 %S A075800 2,3,5,7,11,66,101,131,151,181,191,222,282,313,353,373,383,434,474, %T A075800 494,555,595,606,646,727,757,777,787,797,919,929,969,1001,1221,1551, %U A075800 1771,2222,2882,3333,3553,4334,4994,5335,5555,5665,5885,5995,6006,6226,6446,6886 %N A075800 Palindromic numbers which are products of an odd number of distinct primes. %H A075800 Chai Wah Wu, <a href="/A075800/b075800.txt">Table of n, a(n) for n = 1..10000</a> %e A075800 191 is palindromic and prime, 222=2*3*37 is palindromic and a product of 3 distinct primes. %p A075800 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; %t A075800 Select[Range[10000], PalindromeQ[#] && MoebiusMu[#] == -1 &] (* _Paolo Xausa_, Mar 10 2025 *) %Y A075800 Cf. A002385, A069217, A032350, A030059, A075799, A075806 (first differences). %K A075800 nonn,base %O A075800 1,1 %A A075800 _Jani Melik_, Oct 13 2002 %E A075800 Edited by _Dean Hickerson_, Oct 21 2002