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 A309271 #25 Feb 01 2022 00:29:20 %S A309271 0,0,0,0,0,0,0,0,16,88,464,2076,9904,47456 %N A309271 Number of magic knight's tours on a 4 X 2n board. %D A309271 M. Kraitchik, Mathematical Recreations, Dover, 1953, 257-266. %H A309271 G. P. Jelliss, <a href="http://www.mayhematics.com/t/mo.htm">Oblong Magic Knight Tours</a> %H A309271 Awani Kumar, <a href="https://arxiv.org/abs/1802.09340">Studies in Tours of Knight on Rectangular Boards</a>, arXiv:1802.09340 [math.GM], 2018. %e A309271 An example of a magic knight's tour on a 4 X 18 board. All rows sum to 657 and all columns sum to 146: %e A309271 1 70 33 40 5 42 9 66 29 62 27 58 13 52 25 56 19 50 %e A309271 36 39 4 69 32 65 6 43 10 45 14 61 26 57 20 51 24 55 %e A309271 71 2 37 34 41 8 67 30 63 28 59 12 47 16 53 22 49 18 %e A309271 38 35 72 3 68 31 64 7 44 11 46 15 60 21 48 17 54 23 %Y A309271 Cf. A079137, A123936, A309273. %K A309271 nonn,more %O A309271 1,9 %A A309271 _Awani Kumar_, Jul 20 2019