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A013927 Begin with 2n cards in n piles of 2, the piles being {1,1},{2,2},{3,3},...,{n,n}. How many transpositions of adjacent (single) cards are needed to reverse the order of the piles? 0
0, 2, 5, 10, 15, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

Graham Brightwell, Michael Littman and Peter Winkler (pw(AT)research.bell-labs.com), unpublished.

LINKS

Table of n, a(n) for n=1..6.

CROSSREFS

Sequence in context: A080551 A179207 A008822 * A267454 A163059 A099738

Adjacent sequences:  A013924 A013925 A013926 * A013928 A013929 A013930

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 18 20:42 EDT 2019. Contains 328197 sequences. (Running on oeis4.)