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A035485 Card on top of deck at n-th stage of R. K. Guy's shuffling problem. 21
1, 2, 3, 1, 6, 5, 9, 1, 4, 2, 16, 10, 12, 14, 23, 16, 18, 20, 17, 27, 30, 33, 38, 10, 14, 37, 32, 6, 11, 19, 53, 37, 25, 21, 12, 34, 38, 8, 50, 48, 46, 14, 18, 23, 47, 53, 84, 52, 31, 49, 1, 51, 91, 61, 42, 79, 4, 29, 6, 49, 26, 23, 115, 4, 70, 93, 109, 11, 16, 19, 49, 18, 124, 97, 70, 10, 134, 111, 7, 38, 14, 79, 11, 129 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

At n-th step, pick up top n cards and interlace them with the next n.

Here is the deck after steps 0,1,2,3,4,5:

1,2,3,4,5,6,7,...

2,1,3,4,5,6,7,...

3,2,4,1,5,6,7,...

1,3,5,2,6,4,7,8,9,...

6,1,4,3,7,5,8,2,9,10,...

It is conjectured that eventually every number appears on top of the deck.

REFERENCES

D. Gale, Mathematical Entertainments: "Careful Card-Shuffling and Cutting Can Create Chaos," The Mathematical Intelligencer, vol. 14, no. 1, 1992, pages 54-56.

D. Gale, Tracking the Automatic Ant and Other Mathematical Explorations, A Collection of Mathematical Entertainments Columns from The Mathematical Intelligencer, Springer, 1998.

LINKS

Lars Blomberg, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Perfect Shuffle.

CROSSREFS

See A035491 for the array, also A035490, A035492.

Sequence in context: A110237 A189970 A076631 * A074306 A294218 A036039

Adjacent sequences:  A035482 A035483 A035484 * A035486 A035487 A035488

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane, Clark Kimberling

EXTENSIONS

More terms from Jud McCranie

STATUS

approved

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Last modified February 20 21:53 EST 2018. Contains 299387 sequences. (Running on oeis4.)