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 A174078 #4 Mar 31 2012 19:53:46 %S A174078 20,100,600,4244,34264,311424,3143912,34833964,420917638,5513592091, %T A174078 77715460917 %N A174078 Number of circular permutations of length n with no consecutive triples i,i+2,i+4 or i,i-2,i-4. %C A174078 Circular permutations are permutations whose indices are from the ring of integers modulo n. %e A174078 For n=5 there are (5-1)!-a(5)=4 circular permutations with i,i+2,i+4 or i,i-2,i-4 triples. They are (0,2,4,1,3), (0,2,4,3,1), (0,1,3,4,2), and (0,3,1,4,2). %Y A174078 Cf. A165964, A174076, A174077, A174079. %K A174078 nonn %O A174078 5,1 %A A174078 _Isaac Lambert_, Mar 10 2010 %E A174078 a(10)-a(15) from _Donovan Johnson_, Sep 24 2010