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 A109209 #7 Oct 07 2013 03:29:27
%S A109209 1123211,1412141,3228223,3773773,7949497,9495949,100161001,101060101,
%T A109209 101141101,110232011,111050111,112030211,112111211,113111311,
%U A109209 121111121,122363221,122444221,125252521,131030131,131111131,138313831,138383831
%N A109209 Palindromic primes pp such that digit sum of pp as substring appears more than once in pp.
%e A109209 9495949 is OK because its digit sum 49 appears twice in 9495949.
%t A109209 bb={};Do[id=IntegerDigits[p=Prime[n]];If[StringCount[ToString[p], ToString[Plus@@id]]>1&&Reverse[id]==id, AppendTo[bb, p]], {n, 1000000}];A109209=bb
%Y A109209 Cf. A052019 Sum of digits of prime p is substring of p, A109208 Palindromic primes pp such that digit sum of pp is its substring.
%K A109209 base,nonn
%O A109209 1,1
%A A109209 _Zak Seidov_, Jun 22 2005