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 A264429 #21 Mar 26 2020 15:53:43 %S A264429 1,0,1,0,-1,1,0,1,-3,1,0,0,7,-6,1,0,-5,-10,25,-10,1,0,18,-20,-75,65, %T A264429 -15,1,0,-7,231,70,-315,140,-21,1,0,-338,-840,1064,945,-980,266,-28,1, %U A264429 0,2215,-1278,-8918,1512,4935,-2520,462,-36,1 %N A264429 Triangle read by rows, inverse Bell transform of Bell numbers. %H A264429 Peter Luschny, <a href="https://oeis.org/wiki/User:Peter_Luschny/BellTransform">The Bell transform</a> %e A264429 [ 1 ] %e A264429 [ 0, 1 ] %e A264429 [ 0, -1, 1 ] %e A264429 [ 0, 1, -3, 1 ] %e A264429 [ 0, 0, 7, -6, 1 ] %e A264429 [ 0, -5, -10, 25, -10, 1 ] %e A264429 [ 0, 18, -20, -75, 65, -15, 1 ] %e A264429 [ 0, -7, 231, 70, -315, 140, -21, 1 ] %e A264429 [ 0, -338, -840, 1064, 945, -980, 266, -28, 1 ] %e A264429 [ 0, 2215, -1278, -8918, 1512, 4935, -2520, 462, -36, 1 ] %t A264429 rows = 10; %t A264429 M = Table[BellY[n, k, BellB[Range[0, rows-1]]],{n, 0, rows-1}, {k, 0, rows-1}] // Inverse; %t A264429 A264429 = Table[M[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* _Jean-François Alcover_, Jun 22 2018 *) %o A264429 (Sage) # uses[bell_transform from A264428] %o A264429 def inverse_bell_transform(dim, L): %o A264429 M = matrix(ZZ, dim) %o A264429 for n in range(dim): %o A264429 row = bell_transform(n, L) %o A264429 for k in (0..n): M[n,k] = row[k] %o A264429 return M.inverse() %o A264429 def A264429_matrix(dim): %o A264429 uno = [1]*dim %o A264429 bell_numbers = [sum(bell_transform(n, uno)) for n in range(dim)] %o A264429 return inverse_bell_transform(dim, bell_numbers) %o A264429 A264429_matrix(10) %Y A264429 Cf. A000110, A264428. %K A264429 sign,tabl %O A264429 0,9 %A A264429 _Peter Luschny_, Nov 13 2015