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 A069867 #12 Dec 07 2018 17:23:39
%S A069867 2,3,5,7,23,29,31,37,53,59,71,73,79,131,137,139,173,179,233,239,373,
%T A069867 379,431,433,439,479,673,677,733,739,839,971,977,1319,1373,1733,2237,
%U A069867 2239,2293,2297,2711,2713,2719,3313,3319,3371,3373,3533,3539,3593,3733
%N A069867 Primes in which repeatedly deleting the least significant digit then the most significant digit gives a prime at every step until a single-digit prime remains.
%H A069867 Michael De Vlieger, <a href="/A069867/b069867.txt">Table of n, a(n) for n = 1..440</a> (Primes p <= 5 * 10^7).
%t A069867 Select[Prime@ Range@ 512, AllTrue[FromDigits /@ Rest@ Fold[Append[#1, Delete[Last[#1], 1 - 2 Boole[OddQ@ #2]]] &, {#}, Range[Length@ # - 1]] &@ IntegerDigits[#], PrimeQ] &] (* _Michael De Vlieger_, Jan 20 2018 *)
%Y A069867 Cf. A033664, A024770, A069866.
%K A069867 base,nonn
%O A069867 1,1
%A A069867 _Amarnath Murthy_, Apr 21 2002
%E A069867 Corrected and extended by Larry Reeves (larryr(AT)acm.org), Sep 24 2002