1,7

M. D. Atkinson, M. M. Murphy and N. Ruskuc, Sorting with two ordered stacks in series, Theoret. Comput. Sci. 289 (2002), 205-223.

R. E. Tarjan, Sorting using networks of queues and stacks, JACM, 19 (1972), 341-346.

V. Vatter, The Enumeration and Structure of Permutation Classes, Ph. D. Dissertation, Rutgers Univ., Math. Dept., 2006.

Sequence in context: A043948 A015226 A092221 this_sequence A101571 A122502 A063302

Adjacent sequences: A111573 A111574 A111575 this_sequence A111577 A111578 A111579

nonn

N. J. A. Sloane (njas(AT)research.att.com), Nov 17 2005