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 A006845 M2295 #24 Apr 03 2020 07:52:47
%S A006845 0,1,3,3,140,420,840,840,10810800,75675600,454053600,2270268000,
%T A006845 9081072000,27243216000,54486432000,54486432000,52401161274029568000,
%U A006845 786017419110443520000,11004243867546209280000,143055170278100720640000
%N A006845 State assignments for n-state machine.
%C A006845 After the initial 0, this sequence is formed by taking in turn the last 2^(n-1) elements of row n in the irregular triangle A133709. - _Sean A. Irvine_, Aug 14 2017
%D A006845 F. J. Hill and G. R. Peterson, Introduction to Switching Theory and Logical Design. Wiley, NY, 3rd ed., 1981, p. 308.
%D A006845 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006845 D. Fielder, <a href="/A006845/a006845.pdf">Letters to N. J. A. Sloane (with attachment), 1991</a>
%t A006845 T[m_, l_] := T[m, l] = If[l == 1, 1, Sum[(-1)^i Binomial[l, i]* Binomial[2^(l - i) + m - 2, m], {i, 0, l - 1}] - Sum[StirlingS2[l, i]* T[m, i], {i, 1, l - 1}]];
%t A006845 Join[{{0}}, Table[Table[T[m, l], {l, 2^m - 2^(m-1), 2^m - 1}], {m, 1, 5}]] // Flatten (* _Jean-François Alcover_, Apr 03 2020 *)
%Y A006845 Cf. A007041, A133709.
%K A006845 nonn
%O A006845 1,3
%A A006845 _N. J. A. Sloane_
%E A006845 a(9) corrected and more terms from _Sean A. Irvine_, Aug 14 2017