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 A258183 #4 May 23 2015 04:18:49
%S A258183 7,9,49,111,1090909,28571427,111111111,3333333327,25641025641,
%T A258183 10576923076923,59090909090909,2631578947368421,4827586206896549,
%U A258183 8947368421052631,18644067796610169,111111111111111111,812499999999999999,1889250814332247557,9189189189189189189
%N A258183 Numbers which divide the concatenation of the two surrounding primes.
%C A258183 The terms greater than 10^18 are obtained assuming that nextprime(n) < n + (log n)^2, which is known to hold at least for 4 < n < 10^18.
%H A258183 Giovanni Resta, <a href="/A258183/b258183.txt">Table of n, a(n) for n = 1..42</a> (terms < 10^36)
%H A258183 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_786.htm">Puzzle 786</a>
%e A258183 The number 9 is in the sequence because the surrounding primes are 7 and 11 and 711 is divisible by 9.
%t A258183 Select[Range[3, 10^4], Divisible[ FromDigits[ Join@@ IntegerDigits@ NextPrime[#, {-1, 1}]], #]&]
%Y A258183 Cf. A258182, A258184.
%K A258183 nonn,base
%O A258183 1,1
%A A258183 _Giovanni Resta_, May 23 2015