A123398 Topswops: number of permutations of cards achieving A000375(n).

1, 1, 2, 2, 1, 5, 2, 1, 1, 1, 1, 1, 1, 4, 6, 1, 2, 1, 4

Offset: 1

Author

N. J. A. Sloane, Oct 15 2006

Keywords

• nonn
• more

References

• D. E. Knuth, TAOCP, Section 7.2.1.2, Problems 107-109.

Links

• Kento Kimura, Atsuki Takahashi, Tetsuya Araki, and Kazuyuki Amano, Maximum Number of Steps of Topswops on 18 and 19 Cards, arXiv:2103.08346 [cs.DM], 2021.
• Yuichi Komano and Takaaki Mizuki, Physical Zero-Knowledge Proof Protocol for Topswops, Int'l Conf. Info. Sec. Practice and Experience (ISPEC 2022) Lecture Notes in Comp. Sci. book series (LNCS Vol. 13620) Springer, Cham, 537-553.

Crossrefs

Cf. A000375.

Extensions

Added a(17)=2 using comments in A000375 from Quan T. Nguyen, William Fahle; by Moritz Franckenstein, Nov 27 2010

a(18)-a(19) from Kimura et al. added by Andrey Zabolotskiy, Mar 24 2021