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 A080390 #11 Oct 26 2019 22:26:19
%S A080390 1,5,14,27,34,11,62,183,98,39,142,107,220,69,44,495,322,143,436,139,
%T A080390 482,637,574,119,674,233,782,55,898,29,1146,4063,230,441,174,467,1516,
%U A080390 493,662,239,1762,377,2020,175,764,781,2302,2543,2596,949,968,207,3126,1241
%N A080390 Least x such that gcd(A001405(x+1), A001405(x)) = n.
%F A080390 a(n) = Min{x; A057977(x)=n}.
%t A080390 f[x_] := GCD[Binomial[x+1, Floor[x+1/2]], Binomial[x, Floor[x/2]]] t=Table[0, {257}]; Do[s=f[n]; If[s<258&&t[[s]]==0, t[[s]]=n], {n, 1, 10000}]; t
%Y A080390 Cf. A001405, A057977, A080389.
%K A080390 nonn
%O A080390 1,2
%A A080390 _Labos Elemer_, Mar 12 2003