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 A324262 #14 Mar 16 2019 13:13:35 %S A324262 0,0,0,0,13731373,1190911909,0,19090911909091,0,0,0,0,0,0,0,0,0,0,0,0, %T A324262 7316763215964848081373167632159648480813, %U A324262 111272689909091345969111272689909091345969,10527889691056689261011052788969105668926101,0,0,0,0 %N A324262 a(n) is the smallest term of A324261 with 2n digits if it exists, otherwise 0. %C A324262 There can be a large number of terms in A324261 with 2n digits. For example, there are 227 terms with length 66. Selecting only the smallest term for each length allows terms to be listed for larger values of n. %C A324262 The terms of A324261 with length 2n are formed by concatenating two copies of prime p, where p has length n and the decimal representation of p contains all the prime factors of 10^n + 1 as described in A324261 and A083359. %C A324262 Subsequence of A020338 (Doublets: base-10 representation is the juxtaposition of two identical strings). %H A324262 Deron Stewart, <a href="/A324262/b324262.txt">Table of n, a(n) for n = 0..61</a> %e A324262 With m = 27 there are three prime p's: 114175966169705419295257913, 352579141759661697054192911 and 525791141759661697054192913. The smallest p concatenated with itself gives a(27) = 114175966169705419295257913114175966169705419295257913. %e A324262 With m = 28 there are no solutions so a(28) = 0. %Y A324262 Cf. A083359, A020338, A324261, A324257. %K A324262 nonn,base %O A324262 0,5 %A A324262 _Deron Stewart_, Mar 13 2019