%I M3546 #31 Jan 17 2018 19:08:47

%S 0,1,4,18,105,636,4710,38508,352902,3563297,39467081,475326930,

%T 6198134207,86912048471,1305146666727,20897040866280

%N Number of unreformed permutations of {1,...,n}.

%D A. M. Bersani, "Reformed permutations in Mousetrap and its generalizations", preprint MeMoMat n. 15/2005.

%D R. K. Guy and R. J. Nowakowski, "Mousetrap," in D. Miklos, V. T. Sos and T. Szonyi, eds., Combinatorics, Paul Erdős is Eighty. Bolyai Society Math. Studies, Vol. 1, pp. 193-206, 1993.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H A. M. Bersani, <a href="http://www.dmmm.uniroma1.it/~bersani/mousetrap.html">On the game Mousetrap</a>.

%H A. M. Bersani, <a href="http://www.emis.de/journals/INTEGERS/papers/kg1/kg1.Abstract.html">Reformed Permutations in mousetrap and its generalizations</a>, INTEGERS, 10 (2010), #G01.

%H R. K. Guy and R. J. Nowakowski, <a href="/A002467/a002467_1.pdf">Mousetrap</a>, Preprint, Feb 10 1993 [Annotated scanned copy]

%H R. K. Guy and R. J. Nowakowski, <a href="http://www.jstor.org/stable/2975171">Mousetrap</a>, Amer. Math. Monthly, 101 (1994), 1007-1010.

%F a(n) = n! - A007709(n). - _Sean A. Irvine_, Jan 17 2018

%e For n=3, the 4 unreformed permutations are 123, 231, 312, 213, so a(3)=4. Also 132->123, 321->213 are reformable.

%Y Cf. A007709, A007712, A055459, A067950.

%K nonn,more

%O 1,3

%A _N. J. A. Sloane_

%E More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Mar 06 2002

%E 2 more terms from Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 07 2007

%E One more term from Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 24 2008

%E a(1) corrected by _Joerg Arndt_, Dec 24 2014