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 A321049 #8 Oct 26 2018 19:46:42 %S A321049 0,5,18,44,116,331,932,2532,6720,17804,47280,125460,331736,874973, %T A321049 2305750,6075184,16001968,42130767,110885496,291792264,767776064, %U A321049 2020061968,5314529928,13981117152,36779372688,96751538581,254510051546,669494097852,1761102380100 %N A321049 Number of permutations of [n] with no fixed points where the maximal displacement of an element equals three. %H A321049 Alois P. Heinz, <a href="/A321049/b321049.txt">Table of n, a(n) for n = 3..1000</a> %H A321049 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (3,0,-3,6,-7,-11,-14,0,16,18,6,-7,1,-2,1,-2,-1,1). %F A321049 G.f.: (x^10-x^9-2*x^8+3*x^7-x^6+2*x^5-7*x^4+x^3+10*x^2-3*x-5) * x^4 / ((x+1) *(x^4-2*x^3+x^2-2*x+1) *(x^13-x^11+x^10-x^9-x^8-9*x^7-3*x^6+3*x^5+7*x^4-x^3+x^2+2*x-1)). %F A321049 a(n) = A079997(n) - A033305(n). %Y A321049 Column k=3 of A259784. %Y A321049 Cf. A033305, A079997. %K A321049 nonn,easy %O A321049 3,2 %A A321049 _Alois P. Heinz_, Oct 26 2018