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

1,3

References

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

Links

Table of n, a(n) for n=1..19.

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.

Sequence in context: A332963 A203953 A326933 * A277495 A188945 A281261

Adjacent sequences: A123395 A123396 A123397 * A123399 A123400 A123401

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 15 2006

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

Status

approved