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 A089141 #5 Feb 22 2013 14:38:50 %S A089141 1,2,1,1,3,1,3,5,4,1,1,13,11,5,1,2,23,37,19,6,1,1,51,107,81,29,7,1,4, %T A089141 97,332,319,151,41,8,1,1,207,985,1295,749,253,55,9,1,2,401,2992,5161, %U A089141 3774,1511,393,71,10,1,1,825,8939,20725,19021,9107,2743,577,89,11,1 %N A089141 Square array, read by antidiagonal: T(n,k) = n*T(n,k-1)+(-1)^k*T(n,floor(k/2)). %e A089141 Row 1 :1, 2, 1, 3, 1, 2, 1, 2, 1, 4, 1, 2, 1, ...(A001511). %e A089141 Row 2 :1, 3, 5, 13, 23, 51, 97, 207, 401, 825, 1627, ...(A089067). %e A089141 Row 3 :1, 4, 11, 37, 107, 332, 985, 2992, 8939, 26924, 80665, ... %e A089141 Row 4 :1, 5, 19, 81, 319, 1295, 5161,20725, 82819, 331595, 1326061, ... %e A089141 Row 5 :1, 6, 29, 151, 749, 3774, 19021, 94954, 475519, 2376846, 11888004, ... %Y A089141 Cf. A001511, A089067. %K A089141 easy,nonn,tabl %O A089141 1,2 %A A089141 _Philippe Deléham_, Dec 05 2003