1,3

The Peczarski paper in Algorithmica has a table giving upper and lower bounds that differ by at most 1. In particular, the values a(20) = 62 and a(21) = 66 are also known. - Bodo Manthey, Mar 01 2007

D. E. Knuth, Art of Computer Programming, Vol. 3, 2nd. edition, Sect. 5.3.1.

Marcin Peczarski, Sorting 13 Elements Requires 34 Comparisons, Proc. of the 10th European Symp. on Algorithms (ESA), vol. 2452 of Lecture Notes in Comput. Sci., pp. 785-794. Springer, 2002.

Marcin Peczarski, New Results in Minimum-Comparison Sorting. Algorithmica 40(2):133-145, 2004.

E. Reingold, J. Nievergelt and N. Deo, Combinatorial Algorithms, Prentice-Hall, 1977, section 7.4, p. 309.

Tianxing Tao, On optimal arrangement of 12 points, pp. 229-234 in Combinatorics, Computing and Complexity, ed. D. Du and G. Hu, Kluwer, 1989. [Finds a(12).]

M. Peczarski, The Ford-Johnson algorithm still unbeaten for less than 47 elements

Index entries for sequences related to sorting

A001768 is an upper bound, A003070 a lower bound.

Sequence in context: A062430 A016040 A003070 this_sequence A001768 A089108 A029899

Adjacent sequences: A036601 A036602 A036603 this_sequence A036605 A036606 A036607

nonn,nice,hard

N. J. A. Sloane (njas(AT)research.att.com).

a(13) was determined by Marcin Peczarski. - Bodo Manthey, Sep 25 2002.

a(14)=38 and a(22)=71 were determined by Marcin Peczarski. - Bodo Manthey (manthey(AT)cs.uni-sb.de), Feb 28 2007