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 A264431 #18 Mar 26 2020 15:54:49 %S A264431 1,0,1,0,-1,1,0,1,-3,1,0,-1,7,-6,1,0,2,-15,25,-10,1,0,-8,37,-90,65, %T A264431 -15,1,0,27,-133,322,-350,140,-21,1,0,-70,587,-1330,1757,-1050,266, %U A264431 -28,1,0,265,-2526,6607,-9114,7077,-2646,462,-36,1 %N A264431 Triangle read by rows, inverse Bell transform of second order Bell numbers (A187761). %H A264431 Peter Luschny, <a href="https://oeis.org/wiki/User:Peter_Luschny/BellTransform">The Bell transform</a> %e A264431 [ 1 ] %e A264431 [ 0, 1 ] %e A264431 [ 0, -1, 1 ] %e A264431 [ 0, 1, -3, 1 ] %e A264431 [ 0, -1, 7, -6, 1 ] %e A264431 [ 0, 2, -15, 25, -10, 1 ] %e A264431 [ 0, -8, 37, -90, 65, -15, 1 ] %e A264431 [ 0, 27, -133, 322, -350, 140, -21, 1 ] %e A264431 [ 0, -70, 587, -1330, 1757, -1050, 266, -28, 1 ] %e A264431 [ 0, 265, -2526, 6607, -9114, 7077, -2646, 462, -36, 1 ] %o A264431 (Sage) # uses[bell_transform from A264428, inverse_bell_transform from A264429] %o A264431 def A264431_matrix(dim): %o A264431 uno = [1]*dim %o A264431 bell_numbers = [sum(bell_transform(n, uno)) for n in range(dim)] %o A264431 bell_number_2 = [sum(bell_transform(n, bell_numbers)) for n in range(dim)] %o A264431 return inverse_bell_transform(dim, bell_number_2) %o A264431 A264431_matrix(10) %Y A264431 Cf. A000110, A187761, A264428, A264429. %K A264431 sign,tabl %O A264431 0,9 %A A264431 _Peter Luschny_, Nov 13 2015