A067950 - OEIS

%I #9 Jun 03 2019 00:46:23

%S 1,0,1,8,31,56,219,605,2485,9697,40571

%N a(n) = number of 3-times (but not 4-times) reformable permutation 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.

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

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

%e a(6)=1, 165342->132564->125346->136524.

%Y Cf. A007709, A007711, A007712, A055459.

%K more,nonn

%O 6,4

%A 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