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 A095818 #12 Aug 31 2018 20:04:14
%S A095818 1,1,2,6,24,118,714,5012,40164,361872,3621366,39854930,478427452,
%T A095818 6221137644,87112280208,1306869108686,20912175669082,355537064658852,
%U A095818 6400095163337508,121608318630457872,2432271817858395382,51079520016325649394,1123782363517325646716
%N A095818 Number of permutations of 1..n with no five elements in correct or reverse order.
%C A095818 For no k do either of the subsequences k(k+1)(k+2)(k+3)(k+4) or (k+4)(k+3)(k+2)(k+1)k occur in any permutation.
%H A095818 Andrew Howroyd, <a href="/A095818/b095818.txt">Table of n, a(n) for n = 0..200</a>
%H A095818 D. M. Jackson and R. C. Read, <a href="http://gdz.sub.uni-goettingen.de/dms/load/img/?PID=GDZPPN002031183">A note on permutations without runs of given length</a>, Aequationes Math. 17 (1978), no. 2-3, 336-343.
%F A095818 G.f.: Sum_{n>=0} n!*((2*x^m-x^(m+1)-x)/(x^m-1))^n where m = 5. - Ivana Jovovic ( ivana121(AT)EUnet.yu ), Nov 11 2007
%o A095818 (PARI) seq(n)={my(m=5); Vec(sum(k=0, n, k!*((2*x^m-x^(m+1)-x)/(x^m-1) + O(x*x^n))^k))} \\ _Andrew Howroyd_, Aug 31 2018
%Y A095818 Cf. A002464, A095816, A095817.
%K A095818 nonn
%O A095818 0,3
%A A095818 _Jonas Wallgren_, Jun 08 2004
%E A095818 More terms from Ivana Jovovic ( ivana121(AT)EUnet.yu ), Nov 11 2007
%E A095818 a(0)=1 prepended and terms a(20) and beyond from _Andrew Howroyd_, Aug 31 2018