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 A156116 #17 Feb 23 2019 19:52:02
%S A156116 12421,12541,12641,12653,12721,12743,12763,12821,12841,12853,12941,
%T A156116 12953,12973,12983,13421,13721,13751,13763,13831,13841,13873,13921,
%U A156116 13931,13963,14543,14621,14653,14731,14741,14753,14821,14831,14843,14851,14951,14983
%N A156116 Five-digit mountain-type primes that increase to and decrease from the central digit, including palindromes.
%C A156116 Sequence is finite, ending with a(185) = 78941.
%H A156116 Nathaniel Johnston, <a href="/A156116/b156116.txt">Table of n, a(n) for n = 1..185</a> (full sequence)
%p A156116 for a from 1 to 9 do for b from a+1 to 9 do for c from b+1 to 9 do for d from 2 to c-1 do for e from 1 to d-1 do n:=10000*a+1000*b+100*c+10*d+e: if(isprime(n))then printf("%d, ",n): fi: od:od:od:od:od: # _Nathaniel Johnston_, Jun 23 2011
%K A156116 nonn,base,easy,fini,full
%O A156116 1,1
%A A156116 _Ki Punches_, Feb 14 2009
%E A156116 Minor edits by _Ray Chandler_, Feb 20 2009