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 A238973 #12 Mar 28 2020 17:45:21 %S A238973 0,0,1,2,1,3,6,2,5,6,10,16,2,6,8,14,16,26,40,3,8,11,18,12,23,36,27,42, %T A238973 64,96,3,9,13,22,15,29,46,32,37,58,88,67,102,152,224,4,11,16,26,19,36, %U A238973 56,20,41,48,74,112,52,80,93,140,208,108,162,240,352,512 %N A238973 The number of arcs from odd to even level vertices in divisor lattice in canonical order. %H A238973 Andrew Howroyd, <a href="/A238973/b238973.txt">Table of n, a(n) for n = 0..2713</a> (rows 0..20) %H A238973 S.-H. Cha, E. G. DuCasse, and L. V. Quintas, <a href="http://arxiv.org/abs/1405.5283">Graph Invariants Based on the Divides Relation and Ordered by Prime Signatures</a>, arxiv:1405.5283 [math.NT], 2014. %F A238973 From _Andrew Howroyd_, Mar 28 2020: (Start) %F A238973 T(n,k) = A238951(A063008(n,k)). %F A238973 T(n,k) = A238964(n,k) - A238972(n,k). %F A238973 T(n,k) = floor(A238964(n,k)/2). (End) %e A238973 Triangle T(n,k) begins: %e A238973 0; %e A238973 0; %e A238973 1, 2; %e A238973 1, 3, 6; %e A238973 2, 5, 6, 10, 16; %e A238973 2, 6, 8, 14, 16, 26, 40; %e A238973 3, 8, 11, 18, 12, 23, 36, 27, 42, 64, 96; %e A238973 ... %Y A238973 Cf. A238960 in canonical order. %Y A238973 Cf. A063008, A238951, A238964, A238972. %K A238973 nonn,tabf %O A238973 0,4 %A A238973 _Sung-Hyuk Cha_, Mar 07 2014 %E A238973 Offset changed and terms a(50) and beyond from _Andrew Howroyd_, Mar 28 2020