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 A065519 #17 Sep 10 2018 10:12:19
%S A065519 0,0,1,2,-2,3,5,0,1,-5,4,6,1,-7,6,8,-1,2,3,-9,12,5,7,1,10,2,-1,-15,10,
%T A065519 6,1,2,-16,17,7,2,-18,19,6,0,3,4,-20,25,3,4,5,6,7,-1,12,8,2,11,15,2,
%U A065519 -28,29,7,2,-30,31,9,0,3,8,-30,43,6,8,5,8,9
%N A065519 a(n) = A064413(n)-n.
%C A065519 Zeros appear at A152458.
%H A065519 Peter Kagey, <a href="/A065519/b065519.txt">Table of n, a(n) for n = 1..10000</a>
%H A065519 J. C. Lagarias, E. M. Rains and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.NT/0204011">The EKG sequence</a>, arXiv:math/0204011 [math.NT], 2002.
%H A065519 J. C. Lagarias, E. M. Rains and N. J. A. Sloane, <a href="http://www.emis.de/journals/EM/expmath/volumes/11/11.3/Lagarias437_446.pdf">The EKG Sequence</a>, Exper. Math. 11 (2002), 437-446.
%H A065519 <a href="/index/Ed#EKG">Index entries for sequences related to EKG sequence</a>
%t A065519 terms = 100;
%t A065519 ekg[s_] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]];
%t A065519 Nest[ekg, {1, 2}, terms-2] - Range[terms] (* _Jean-François Alcover_, Sep 10 2018, after _Robert G. Wilson v_ *)
%Y A065519 Cf. A064413, A152458.
%K A065519 sign
%O A065519 1,4
%A A065519 _N. J. A. Sloane_, Nov 28 2001