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 A089566 #5 Mar 30 2012 17:29:13 %S A089566 11,2,4,3,5,9,1,30,6,20,16,8,24,15,13,39,36,56,64,72,29,49,27,60,54, %T A089566 63,65,45,12,99,28,47,88,51,83,31,59,94,336,108,182,204,184,38,37,188, %U A089566 210,91,62,10,224,202,128,115,66,111,156,566,43,255,279,315,180,257,102,118 %N A089566 a(1) = 11. For n > 1, a(n) is the least unused number such that every concatenation a(n)a(n-1)...a(2)a(1) is prime. %C A089566 Is this a rearrangement of the natural numbers? %Y A089566 Cf. A089710, A089711, A089560-A089573. %K A089566 base,nonn %O A089566 1,1 %A A089566 _Ray Chandler_, Nov 22 2003 %E A089566 Edited by _Charles R Greathouse IV_, Apr 29 2010