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 A028451 #20 Jul 11 2019 10:18:49
%S A028451 1,21,6272,880163,152526845,24972353440,4161756233501,690427159718433,
%T A028451 114725843769441312,19056798015394695543,3165986817537284900809,
%U A028451 525966380704787334395776,87380576637559587656345353,14516824056706613915897809761,2411733911295546238838103099168
%N A028451 Number of perfect matchings in graph P_{2} X P_{7} X P_{n}.
%C A028451 This sequence satisfies a recurrence relation of order 750. - _Sergey Perepechko_, Jul 11 2019
%H A028451 Alois P. Heinz, <a href="/A028451/b028451.txt">Table of n, a(n) for n = 0..450</a>
%H A028451 Per Hakan Lundow, <a href="http://www.theophys.kth.se/~phl/Text/1factors.pdf">Computation of matching polynomials and the number of 1-factors in polygraphs</a>, Research report, No 12, 1996, Department of Math., Umea University, Sweden.
%H A028451 Per Hakan Lundow, <a href="http://www.theophys.kth.se/~phl/Text/1factors2.ps.gz">Enumeration of matchings in polygraphs</a>, 1998.
%H A028451 A. M. Karavaev and S. N. Perepechko, <a href="http://dx.doi.org/10.13140/RG.2.2.13054.13126">Dimer problem on two-layer rectangular grid graph</a>, (in Russian) CMMASS'2013 slides
%H A028451 Sergey Perepechko, <a href="/A028451/a028451.txt">Generating function</a> in Maple notation
%Y A028451 Column k=7 of A181206.
%K A028451 nonn
%O A028451 0,2
%A A028451 _Per H. Lundow_