cp's OEIS Frontend

A335613 Number of sets (in the Hausdorff metric geometry) at each location between two sets defined by a complete bipartite graph K(4,n) (with n at least 3) missing two edges, where the removed edges are incident to the same vertex in the four point part.

%I A335613 #37 Jun 27 2023 11:10:43
%S A335613 290,7568,140114,2300576,35939330,549221168,8309585714,125143712576,
%T A335613 1880658325730,28234402793168,423687765591314,6356518634756576,
%U A335613 95356194832648130,1430401830434093168,21456439814417820914,321849483728499752576,4827762461533785786530
%N A335613 Number of sets (in the Hausdorff metric geometry) at each location between two sets defined by a complete bipartite graph K(4,n) (with n at least 3) missing two edges, where the removed edges are incident to the same vertex in the four point part.
%C A335613 The Hausdorff metric defines a distance between sets. Using this distance we can define line segments with sets as endpoints. Create two sets from the vertices of the parts A and B (with |A| = 4) of a complete bipartite graph K(4,n) (with n at least 3) missing two edges, where the removed edges are incident to the same point in A. Points in the sets A and B that correspond to vertices that are connected by edges are the same Euclidean distance apart. This sequence tells the number of sets at each location on the line segment between A and B.
%C A335613 Number of {0,1} 4 X n (with n at least 3) matrices with two fixed zero entries in the same row and no zero rows or columns.
%C A335613 Take a complete bipartite graph K(4,n) (with n at least 3) having parts A and B where |A| = 4. This sequence gives the number of edge covers of the graph obtained from this K(4,n) graph after removing two edges, where the two removed edges are incident to the same vertex in A.
%H A335613 Steven Schlicker, Roman Vasquez, and Rachel Wofford, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL26/Wofford/wofford4.html">Integer Sequences from Configurations in the Hausdorff Metric Geometry via Edge Covers of Bipartite Graphs</a>, J. Int. Seq. (2023) Vol. 26, Art. 23.6.6.
%H A335613 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (26,-196,486,-315).
%F A335613 a(n) = 49*15^(n-2) - 76*7^(n-2) + 10*3^(n-1) - 3.
%F A335613 From _Colin Barker_, Jul 17 2020: (Start)
%F A335613 G.f.: 2*x^3*(145 + 14*x + 93*x^2) / ((1 - x)*(1 - 3*x)*(1 - 7*x)*(1 - 15*x)).
%F A335613 a(n) = 26*a(n-1) - 196*a(n-2) + 486*a(n-3) - 315*a(n-4) for n>6.
%F A335613 (End)
%p A335613 a:= proc(n) 49*15^(n-2)-76*7^(n-2)+10*3^(n-1)-3 end proc: seq(a(n), n=3..20);
%o A335613 (PARI) Vec(2*x^3*(145 + 14*x + 93*x^2) / ((1 - x)*(1 - 3*x)*(1 - 7*x)*(1 - 15*x)) + O(x^22)) \\ _Colin Barker_, Jul 17 2020
%Y A335613 Sequences of segments from removing edges from bipartite graphs A335608-A335613, A337416-A337418, A340173-A340175, A340199-A340201, A340897-A340899, A342580, A342796, A342850, A340403-A340405, A340433-A340438, A341551-A341553, A342327-A342328, A343372-A343374, A343800. Polygonal chain sequences A152927, A152928, A152929, A152930, A152931, A152932, A152933, A152934, A152939. Number of {0,1} n X n matrices with no zero rows or columns A048291.
%K A335613 easy,nonn
%O A335613 3,1
%A A335613 _Steven Schlicker_, Jul 16 2020