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 A374086 #7 Jun 30 2024 22:09:51
%S A374086 1,2,18,288,14760
%N A374086 Number of integer sequences on a circle of length A373728(n) containing all permutations of the set {1, 2, ..., n} as subsequences.
%C A374086 a(n) is a multiple of n!.
%e A374086 a(1) = 1 as '1' is the only sequence of length A373728(1) = 1.
%e A374086 a(2) = 2 corresponding to the sequences of length A373728(2) = 2 : {'12', '21'}.
%e A374086 a(3) = 18 corresponding to the sequences of length A062714(3) = 4 : {'1213', '1231', '1232', '1312', '1321', '1323', '2123', '2131', '2132', '2312', '2313', '2321', '3121', '3123', '3132', '3212', '3213', '3231'}.
%Y A374086 Cf. A062714, A373728, A374085.
%K A374086 nonn,hard,more
%O A374086 1,2
%A A374086 _Chai Wah Wu_, Jun 27 2024