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 A231442 #15 Dec 23 2024 14:53:43
%S A231442 1,3,2,9,5,11,8,12,4,7,6,10,13,15,14,17,18,16,19,21,22,30,20,23,24,29,
%T A231442 26,27,25,31,28,33,32,35,36,34,37,39,38,41,42,43,45,47,44,51,40,49,46,
%U A231442 57,50,53,48,59,56,63,52,61,54,67,55,69,58,70,60,71,62,72,64,73,66,79,75,65,74,68,77
%N A231442 The digits of a(n) and a(n+1) taken together are the digits of a prime; least permutation of the positive integers with this property.
%H A231442 Lars Blomberg, <a href="/A231442/b231442.txt">Table of n, a(n) for n = 1..10000</a>
%H A231442 M. F. Hasler, in reply to E. Angelini, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2013-November/011858.html">Two make a prime</a>, SeqFan list, Nov 09 2013
%e A231442 Start with a(1)=1. The same number cannot be used twice, so the least prime that can be made with this digit is 13, so a(2)=3.
%o A231442 (PARI) {a=1;u=0;for(n=1,99,u+=1<<a;print1(a",");for(k=1,9e9,bittest(u,k)&&next;d=Vec(Str(a,k));for(p=0,(#d)!-1, isprime(eval(concat(t=vecextract(d, numtoperm(#d, p)))))&&t[1]>"0"&&(a=k)&&next(3))))}
%Y A231442 Cf. A231433 (analog for nonnegative integers).
%K A231442 nonn,base
%O A231442 1,2
%A A231442 _M. F. Hasler_, Nov 09 2013