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A007974 Number of permutations that are n-3 "block reversals" away from 12...n. 4
1, 6, 52, 389, 2539, 16604, 105365, 654030, 3900116 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Table of n, a(n) for n=3..11.

FORMULA

a(n) = A300003(n,n-3).

CROSSREFS

Cf. A007972, A007973, A007975, A300003.

Sequence in context: A292053 A202925 A287082 * A027111 A083301 A005948

Adjacent sequences:  A007971 A007972 A007973 * A007975 A007976 A007977

KEYWORD

nonn,more

AUTHOR

J. H. Conway

EXTENSIONS

a(9)-a(11) from Sean A. Irvine, Feb 22 2018

STATUS

approved

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Last modified May 24 19:37 EDT 2018. Contains 304533 sequences. (Running on oeis4.)