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 A213852 #12 May 17 2019 11:06:11
%S A213852 2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,2,
%T A213852 1,1,3,1,1,2,1,1,2,1,1,2,1,1,2,1,1,5,1,1,2,1,1,2,1,1,2,1,1,2,1,1,3,1,
%U A213852 1,2,1,1,2,1,1,2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,2,1,1,3,1,1
%N A213852 Least m>0 such that n+1+m and n-m are relatively prime.
%C A213852 a(n) > 1 for n == 1 mod 3, a(n) > 2 for n == 7 mod 15, a(n) > 3 for n == 52 mod 105, a(n) > 5 for n == 577 mod 1155, and so on, see A070826. - _Ralf Stephan_, Mar 16 2014
%C A213852 It appears that we get this sequence if we bisect A071222 and then divide by 2. - _N. J. A. Sloane_, May 17 2019
%H A213852 Clark Kimberling, <a href="/A213852/b213852.txt">Table of n, a(n) for n = 1..1000</a>
%e A213852 gcd(9,6) = 3, gcd(10,5) = 5, gcd(11,4) = 1, so that a(7) = 3.
%t A213852 Table[m = 1; While[GCD[n+1+m,n-m] != 1, m++]; m, {n, 1, 140}]
%Y A213852 Cf. A071222, A195508.
%K A213852 nonn,easy
%O A213852 1,1
%A A213852 _Clark Kimberling_, Jul 26 2012