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 A255198 #54 Feb 28 2015 14:39:12 %S A255198 1,1,1,4,1,6,2,2,5 %N A255198 Let EKG-n denote the EKG sequence (A064413) started with n rather than 2, and suppose EKG-n first merges with some other EKG-i (i >= 2) sequence after f(n) (= A255583(n)) steps; then a(n) = number of i such that EKG-i meets EKG-n after f(n) steps. %C A255198 This sequence can be used in a classroom to introduce students to divisors. %C A255198 For an explanatory video, see the Youtube link. %C A255198 EKG-5 merges with EKG-2 after three steps, so some care is needed in the definition. Perhaps the offset should be 3 rather than 2? - _N. J. A. Sloane_, Feb 24 2015 %C A255198 Merging means that the sequences are identical for all future steps. EKG-2 and EKG-5 merge at step 44. From then on the sequences are identical. %C A255198 EKG-3 and EKG-5 (below) do not merge at step 3, because the sequences are not identical from that point forward. %H A255198 Gordon Hamilton, <a href="http://youtu.be/yd2jr30K2R4">The EKG Sequence and the Tree of Numbers</a>, Oct 2013. %e A255198 a(5) = 4 because the EKG sequence starting with 5 (EKG-5, A169841) starts coinciding with sequences EKG-3, EKG-6, EKG-9 and EKG-12 simultaneously (when all sequences hit 18). %e A255198 EKG-3: 3, 6, 2, 4, 8, 10, 5, 15, 9, 12, 14, 7, 21, 18, 16, 20, 22, 11, ... (A169837) %e A255198 EKG-6: 6, 2, 4, 8, 10, 5, 15, 3, 9, 12, 14, 7, 21, 18, 16, 20, 22, 11, ... (A169843) %e A255198 EKG-9: 9, 3, 6, 2, 4, 8, 10, 5, 15, 12, 14, 7, 21, 18, 16, 20, 22, 11, ... (A169849) %e A255198 EKG-12: 12, 2, 4, 6, 3, 9, 15, 5, 10, 8, 14, 7, 21, 18, 16, 20, 22, 11, ... (A169855) %e A255198 EKG-5: 5, 10, 2, 4, 6, 3, 9, 12, 8, 14, 7, 21, 15, 18, 16, 20, 22, 11, ... (A169841) %e A255198 a(12) = 3 because the EKG sequence starting with 12 (EKG-12, A169855) starts coinciding with sequences EKG-3, EKG-6, and EKG-9 simultaneously (when all sequences hit 14). %Y A255198 Cf. A064413, A169837, A169841, A169843, A169849, A169857, A255583. %Y A255198 A255524 gives the smallest closest neighbor. %K A255198 nonn,more %O A255198 2,4 %A A255198 _Gordon Hamilton_, Feb 16 2015