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 A075805 #17 Mar 10 2025 11:01:57 %S A075805 5,16,11,22,22,34,30,20,41,60,41,20,70,61,51,10,20,10,20,61,81,10,20, %T A075805 30,51,20,20,20,20,41,10,10,20,10,122,330,220,330,11,440,561,110,110, %U A075805 220,440,891,231,110,1551,451,330,550,1122,110,220,552,100,300,400,100 %N A075805 Differences between adjacent palindromic numbers which are products of an even number of distinct primes. %H A075805 Paolo Xausa, <a href="/A075805/b075805.txt">Table of n, a(n) for n = 1..1000</a> %e A075805 a(1)=6-1=5, a(2)=22-6=16. %p A075805 test := proc(n) local d; d := convert(n,base,10); return ListTools[Reverse](d)=d and numtheory[mobius](n)=1; end; s := []; for n from 1 to 11000 do if test(n) then s := [op(s),n]; end; od; a := [op(2..-1,s)-op(1..-2,s)]; %t A075805 Differences[Select[Range[10000], PalindromeQ[#] && MoebiusMu[#] == 1 &]] (* _Paolo Xausa_, Mar 10 2025 *) %Y A075805 Cf. A037010. %Y A075805 First differences of A075799. %K A075805 nonn,base %O A075805 1,1 %A A075805 _Jani Melik_, Oct 13 2002 %E A075805 Edited by _Dean Hickerson_, Oct 21 2002