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 A321000 #12 Oct 29 2018 18:25:43 %S A321000 1,1,2,1,4,5,1,6,23,15,1,8,53,173,52,1,10,95,619,1602,203,1,12,149, %T A321000 1497,8972,17575,877,1,14,215,2951,29362,155067,222497,4140,1,16,293, %U A321000 5125,72852,688439,3109269,3188806,21147,1,18,383,8163,152402,2152651,18766393,70893872,50988405,115975 %N A321000 Array of generalized Bell numbers, read by antidiagonals upwards. %H A321000 Robert Gill, <a href="https://doi.org/10.1016/S0012-365X(97)00187-8">The number of elements in a generalized partition semilattice</a>, Discrete mathematics 186.1-3 (1998): 125-134. See Example 2. (Example 1, read by antidiagonals downwards, is A257565.) %e A321000 The first few antidiagonals are: %e A321000 1, %e A321000 1,2, %e A321000 1,4,5, %e A321000 1,6,23,15, %e A321000 1,8,53,173,52, %e A321000 1,10,95,619,1602,203, %e A321000 ... %Y A321000 The first three rows are A000110, A075729, A109092. %Y A321000 Cf. A257565. %K A321000 nonn,tabl %O A321000 1,3 %A A321000 _N. J. A. Sloane_, Oct 26 2018 %E A321000 More terms from _Ilya Gutkovskiy_, Oct 29 2018