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 A195931 #24 Jan 08 2013 18:08:24 %S A195931 1,1,2,5,16,56,236,998,4544,20346 %N A195931 The number of orbits in S_n by the action of Foata's bijection. %C A195931 Foata's bijection takes a permutation w with maj(w)=x to a permutation F(w) with inv(F(w))=x. Applying F repeatedly partitions the symmetric group into distinct orbits. F also preserves inverse descent sets. %D A195931 James Pfeiffer, personal communication. %H A195931 Dominique Foata and Marcel-Paul Schützenberger, <a href="http://dx.doi.org/10.1002/mana.19780830111">Major Index and inversion number of permutations</a>, Math. Nachr. 83 (1978), 143-159 %e A195931 The orbits of S_4 are: %e A195931 [(1, 2, 3, 4)] %e A195931 [(2, 1, 3, 4)] %e A195931 [(2, 3, 1, 4)] %e A195931 [(2, 3, 4, 1)] %e A195931 [(3, 2, 1, 4)] %e A195931 [(3, 2, 4, 1)] %e A195931 [(3, 4, 2, 1)] %e A195931 [(4, 3, 2, 1)] %e A195931 [(2, 1, 4, 3), (4, 2, 1, 3), (2, 4, 1, 3)] %e A195931 [(2, 4, 3, 1), (4, 2, 3, 1)] %e A195931 [(1, 3, 2, 4), (3, 1, 2, 4)] %e A195931 [(1, 3, 4, 2), (3, 1, 4, 2), (3, 4, 1, 2)] %e A195931 [(1, 4, 3, 2), (4, 3, 1, 2)] %e A195931 [(4, 1, 3, 2)] %e A195931 [(1, 2, 4, 3), (4, 1, 2, 3)] %e A195931 [(1, 4, 2, 3)] %Y A195931 Cf. A195931, A195924, A065161 %K A195931 nonn,hard,more %O A195931 0,3 %A A195931 _Austin Roberts_, Oct 26 2011