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 A214646 #9 Jun 19 2021 11:39:04 %S A214646 1,1,1,2,2,3,2,5,5,7,2,12,9,7,7,16,2,23,9,25,32,34,57,33,91,30,124, %T A214646 121,77,245,18,46,263,32,309,295,341,604,636,945,310,527,251,27,778, %U A214646 278,805,528,1083,1333,537,2416,1870,2953,2143,4823,5096,6966,109 %N A214646 a(n) = (a(n-2) + a(n-3))/gcd(a(n-2), a(n-3)) with a(1) = a(2) = a(3) = 1. %C A214646 A variation on A214551 with the second and third terms being added and divided by the greatest common divisor of the pair of numbers. %H A214646 Reed Kelly, <a href="/A214646/b214646.txt">Table of n, a(n) for n = 1..1003</a> %e A214646 a(6) = (a(4)+a(3))/gcd(a(4),a(3)) = (2+1)/1 = 3. %e A214646 a(19) = (a(17)+a(16))/gcd(a(17),a(16)) = (2+16)/2 = 9. %t A214646 DivGCDxy[n_, x_, y_, init_] := Module[{t, a, i}, t = init; %t A214646 Do[AppendTo[t, (t[[-x]] + t[[-y]])/GCD[t[[-x]], t[[-y]]]], {n}]; %t A214646 t]; DivGCDxy[100, 2, 3, {1, 1, 1}] %Y A214646 Cf. A214551, A000931. %K A214646 nonn %O A214646 1,4 %A A214646 _Reed Kelly_, Jul 24 2012 %E A214646 NAME adapted to offset and b-file. - _R. J. Mathar_, Jun 19 2021