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 A139458 #13 Feb 19 2021 00:03:52 %S A139458 1,1,1,1,1,1,2,3,4,1,1,2,3,1,1,1,2,1,2,1,1,1,3,2,1,1,4,3,2,1,1,1,1,1, %T A139458 1,1,2,3,4,1,1,2,3,1,1,1,2,1,2,1,1,1,3,2,1,1,4,3,2,1,1,1,1,1,1,1,2,3, %U A139458 4,1,1,2,3,1,1,1,2,1,2,1,1,1,3,2,1,1,4,3,2,1,1,1,1,1,1,1,2,3,4 %N A139458 Frieze pattern of order 6, with 5 rows, read by diagonals. %C A139458 Period 30: repeat [1, 1, 1, 1, 1, 1, 2, 3, 4, 1, 1, 2, 3, 1, 1, 1, 2, 1, 2, 1, 1, 1, 3, 2, 1, 1, 4, 3, 2, 1]. - _Wesley Ivan Hurt_, Jun 05 2016 %H A139458 K. Bauer and R. J. Marsh, <a href="http://arxiv.org/abs/0711.1443">Ptolemy relations for punctured discs</a>, arXiv:0711.1443 [math.CO], 2007. %H A139458 <a href="/index/Rec#order_30">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1). %e A139458 The frieze pattern is: %e A139458 ... 1 1 1 1 1 1 1 ... %e A139458 .... 1 2 2 2 1 4 ... %e A139458 ... 3 1 3 3 1 3 8 ... %e A139458 .... 2 1 4 1 2 2 ... %e A139458 ... 1 1 1 1 1 1 1 ... %Y A139458 Cf. A139434, A139438. %K A139458 nonn,tabf %O A139458 0,7 %A A139458 _N. J. A. Sloane_, Jun 09 2008