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 A224289 #17 Jun 23 2017 14:14:17
%S A224289 0,0,0,2,8,26,79,232,664,1856,5072,13568,35584,91648,232192,579584,
%T A224289 1427456,3473408,8359936,19922944,47054848,110231552,256311296,
%U A224289 591921152,1358430208,3099590656,7034896384,15888023552,35718692864,79960211456,178291474432,396076515328,876844417024
%N A224289 Number of permutations of length n containing exactly 1 occurrence of 123 and 2 occurrences of 132.
%H A224289 B. Nakamura, <a href="http://arxiv.org/abs/1301.5080">Approaches for enumerating permutations with a prescribed number of occurrences of patterns</a>, arXiv 1301.5080, 2013.
%H A224289 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (8, -24, 32, -16).
%F A224289 a(n) = 2^(-8+n)*(-136+70*n-11*n^2+n^3) for n>3. G.f.: -x^4*(x^3-10*x^2+8*x-2) / (2*x-1)^4. - _Colin Barker_, Apr 14 2013
%p A224289 # Programs can be obtained from author's personal website.
%t A224289 LinearRecurrence[{8,-24,32,-16},{0,0,0,2,8,26,79},40] (* _Harvey P. Dale_, Jun 23 2017 *)
%Y A224289 Cf. A000079, A001787, A001815, A046718, A001793.
%K A224289 nonn,easy
%O A224289 1,4
%A A224289 _Brian Nakamura_, Apr 03 2013