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 A154656 #23 Jan 29 2019 10:36:20 %S A154656 1,1,2,6,24,120,720,5040,40320,287280,1865520,11345160,66349464, %T A154656 381523758,2193664790,12764590275,75796724309,455383613924, %U A154656 2750869551868,16635586999056,100439873614656,604666567043712,3629299734118656,21736009354060800,130082373922081536 %N A154656 Number of permutations of length n within distance 7. %C A154656 a(n) equals the permanent of the n X n matrix with 1's along the central fifteen diagonals, and 0's everywhere else. - _John M. Campbell_, Jul 10 2011 %H A154656 Alois P. Heinz, <a href="/A154656/b154656.txt">Table of n, a(n) for n = 0..1000</a> (terms n=1..400 from R. H. Hardin) %H A154656 Torleiv Kløve, <a href="http://www.ii.uib.no/publikasjoner/texrap/pdf/2008-376.pdf">Spheres of Permutations under the Infinity Norm - Permutations with limited displacement</a>, Reports in Informatics, Department of Informatics, University of Bergen, Norway, no. 376, November 2008. %Y A154656 Cf. A000045, A002524, A002526, A072856, A154654. %Y A154656 Column k=7 of A306209. %K A154656 nonn,easy %O A154656 0,3 %A A154656 _Torleiv Kløve_, Jan 13 2009 %E A154656 a(0)=1 prepended by _Alois P. Heinz_, Jan 28 2019