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 A075801 #5 Jun 24 2014 01:08:26 %S A075801 3,2,2,1,13,11,11,11,11,11,11,11,12,10,20,20,10,31,10,10,10,10,10,10, %T A075801 10,10,10,11,20,10,10,20,30,11,10,10,10,10,10,10,10,10,10,11,10,10,10, %U A075801 10,10,10,10,10,10,11,10,10,10,10,10,10,10,10,10,11,10,20,10,20,10,31 %N A075801 Differences between adjacent palindromic nonprime numbers A032350. %e A075801 a(1)=4-1=3, a(5)=22-9=13. %p A075801 test := proc(n) local d; d := convert(n,base,10); return ListTools[Reverse](d)=d and not isprime(n); end; s := []; for n from 1 to 1000 do if test(n) then s := [op(s),n]; end; od; a := [op(2..-1,s)-op(1..-2,s)]; %Y A075801 Cf. A037010, A032350. %K A075801 nonn,base %O A075801 1,1 %A A075801 _Jani Melik_, Oct 13 2002 %E A075801 Edited by _Dean Hickerson_, Oct 21 2002