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 A089564 #10 Jan 22 2022 08:47:26 %S A089564 9,1,4,5,3,7,12,11,13,42,26,10,17,16,20,82,29,78,57,27,28,66,45,6,69, %T A089564 33,236,40,116,237,196,65,133,90,60,72,80,61,126,24,153,68,88,122,43, %U A089564 156,231,285,125,177,249,106,36,147,23,208,483,138,281,63,108,22,38,75,159 %N A089564 a(1) = 9. For n > 1, a(n) is the least unused number such that the decimal concatenation a(n)a(n-1)...a(2)a(1) is prime. %C A089564 Is this a permutation of the positive integers? %C A089564 The sequence is infinite by Dirichlet's theorem; Linnik's theorem gives an effectively computable bound on its members. Using Xylouris's version with L <= 5.2, a(n) = 9^(5.2^(n + O(log n))). - _Charles R Greathouse IV_, Apr 27 2010 %Y A089564 Cf. A089710, A089711, A089560-A089573. %K A089564 nonn,base %O A089564 1,1 %A A089564 _Ray Chandler_, Nov 22 2003