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 A124693 #12 Sep 27 2019 12:38:40
%S A124693 1,1,2,4,6,14,16,44,64,82,88,322,338,982,1002,1006,2456,6428,6766,
%T A124693 19622,19710,19728,19874,98556,105322,126042,126510,252610,253612,
%U A124693 1061208,1061210,3183626,4770276,4770358,4772814,4772828,5939358,31392886
%N A124693 a(1)=1. a(n+1) = sum a(k), where the sum is over all positive integers k, k <= n, where each positive integer <= k and coprime to k is also coprime to n.
%e A124693 The positive integers k, where k <= 6 and where each positive integer <= k and coprime to k is also coprime to 6, are 1,2,6. So a(7) = a(1)+a(2)+a(6) = 1+1+14 = 16.
%t A124693 f[n_] := Select[ Range[n], GCD[ #, n] == 1 &]; g[n_] := Select[ Range[n], Times @@ GCD[f[ # ], n] == 1 &]; h[l_List] := Append[l, Plus @@ l[[g[Length[l]]]]]; Nest[h, {1}, 38] (* _Ray Chandler_, Dec 26 2006 *)
%Y A124693 Cf. A126260.
%K A124693 nonn
%O A124693 1,3
%A A124693 _Leroy Quet_, Dec 25 2006
%E A124693 Extended by _Ray Chandler_, Dec 26 2006