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 A228167 #20 May 22 2017 08:06:55 %S A228167 1,1,4,16,28,38,28,16,4,1,1,4,36,140,476,1092,2044,2860,3270,2860, %T A228167 2044,1092,476,140,36,4,1,1,8,84,536,2770,10808,34116,87144,185071, %U A228167 328208,492392,625968,678524,625968,492392,328208,185071,87144,34116,10808,2770,536,84,8,1 %N A228167 Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (8,n)-rectangular grid with k '1's and (8n-k) '0's: two patterns are in the same class if one of them can be obtained by a reflection or 180-degree rotation of the other. %C A228167 The length of row n is 8*n+1. %C A228167 Sum of rows (see example) gives A225832. %C A228167 This triangle is to A225828 as Losanitsch's triangle A034851 is to A005418, triangle A226048 to A225826, triangle A226290 to A225827, triangle A225812 to A225828, triangle A228022 to A225829, triangle A228165 to A225830, and triangle A228166 to A225831. %C A228167 Also the number of equivalence classes of ways of placing k 1 X 1 tiles in an n X 8 rectangle under all symmetry operations of the rectangle. - _Christopher Hunt Gribble_, Feb 28 2014 %H A228167 Yosu Yurramendi and María Merino, <a href="/A228167/b228167.txt">Rows n = 0..20 of irregular triangle, flattened</a> %e A228167 Irregular triangle: %e A228167 1 %e A228167 1 4 16 28 38 28 16 4 1 %e A228167 1 4 36 140 476 1092 2044 2860 3270 2860 2044 1092 ... %e A228167 1 8 84 536 2770 10808 34116 87144 185071 328208 492392 625968 678524 625968 492392 ... %Y A228167 Cf. A225826-A225831, A005418, A034851, A226048, A226290, A225812, A228022, A228165, A228166. %K A228167 nonn,tabf %O A228167 0,3 %A A228167 _Yosu Yurramendi_, _María Merino_, Aug 14 2013 %E A228167 Definition corrected by _María Merino_, May 22 2017