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 A324015 #5 Feb 12 2019 22:36:31
%S A324015 0,1,2,3,6,10,17,28,46,75,122,198,321,520,842,1363,2206,3570,5777,
%T A324015 9348,15126,24475,39602,64078,103681,167760,271442,439203,710646,
%U A324015 1149850,1860497,3010348,4870846,7881195,12752042,20633238,33385281,54018520,87403802
%N A324015 Number of nonempty subsets of {1, ..., n} containing no two cyclically successive elements.
%C A324015 Cyclically successive means 1 succeeds n.
%C A324015 After a(1) = 1, same as A001610 shifted once to the right. Also, a(n) = A169985(n) - 1.
%F A324015 For n <= 3, a(n) = n. Otherwise, a(n) = a(n - 1) + a(n - 2) + 1.
%e A324015 The a(6) = 17 stable subsets:
%e A324015 {1}, {2}, {3}, {4}, {5}, {6},
%e A324015 {1,3}, {1,4}, {1,5}, {2,4}, {2,5}, {2,6}, {3,5}, {3,6}, {4,6},
%e A324015 {1,3,5}, {2,4,6}.
%t A324015 stabsubs[g_]:=Select[Rest[Subsets[Union@@g]],Select[g,Function[ed,UnsameQ@@ed&&Complement[ed,#]=={}]]=={}&];
%t A324015 Table[Length[stabsubs[Partition[Range[n],2,1,1]]],{n,0,10}]
%Y A324015 Cf. A000045, A000126, A000296, A001610, A001644, A169985, A306357, A324014.
%K A324015 nonn
%O A324015 0,3
%A A324015 _Gus Wiseman_, Feb 12 2019