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 A209332 #20 Feb 01 2014 07:20:12 %S A209332 1,1,1,1,1,1,2,2,1,1,2,1,3,5,1,1,1,1,1,2,1,1,1,3,0,3,1,1,1,1,2,4,0,3, %T A209332 2,1,0,4,1,1,1,1,1,2,1,1,0,5,0,3,2,1,0,7,2,2,1,1,2,1,0,8,1,2,1,1,1,2, %U A209332 1,1,1,1,0,7,1,2,1,1,3,2,1,1,0,3,0,4,3 %N A209332 a(n) is the minimal positive number k such that n<+>k is prime or 0 if no such number exists (operation <+> defined in A206853). %C A209332 Numbers n for which a(n) = 1 form sequence A208982. %C A209332 a(n) = 0 for n = 25, 33, 37, 47,... (A209333). %C A209332 A simple sufficient condition for a(n) = 0 (which is proved by induction) is that n<+>k is not prime up to the moment that n<+>k is even and n<+>(k+1)-n<+>k = 2^t, where t >= m+1 and m defined by the condition 2^m <= n < 2^(m+1). %C A209332 Conjecture: for even n, a(n) > 0. %Y A209332 Cf. A205509, A205510, A205511, A205302, A205649, A205533, A122565, A206852, A206853, A206960, A209085, A208982, A209085, A209333. %K A209332 nonn,base %O A209332 1,7 %A A209332 _Vladimir Shevelev_, Mar 06 2012