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 A007041 M2016 #20 Nov 06 2017 02:41:39
%S A007041 2,12,12,1120,3360,6720,6720,172972800,1210809600,7264857600,
%T A007041 36324288000,145297152000,435891456000,871782912000,871782912000,
%U A007041 1676837160768946176000,25152557411534192640000,352135803761478696960000,4577765448899223060480000
%N A007041 State assignments for n-state machine.
%D A007041 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%D A007041 P. E. Wood, Jr., Switching Theory, McGraw-Hill, 1968, see p. 263.
%H A007041 Michael De Vlieger, <a href="/A007041/b007041.txt">Table of n, a(n) for n = 2..410</a>
%H A007041 D. Fielder, <a href="/A006845/a006845.pdf">Letters to N. J. A. Sloane (with attachment), 1991</a>
%F A007041 a(n) = (2^s)!/((2^s-n)!*s!) where s = ceiling(log_2 n).
%t A007041 Array[(2^#2)!/((2^#2 - #1)!*#2!) & @@ {#, Ceiling@ Log2@ #} &, 19, 2] (* _Michael De Vlieger_, Nov 05 2017 *)
%Y A007041 Cf. A006845.
%K A007041 nonn
%O A007041 2,1
%A A007041 _N. J. A. Sloane_
%E A007041 More terms and formula corrected by _Sean A. Irvine_, Sep 24 2017