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A180112 Number of permutations of 1..n with the Sum_{i=1..n} of (i-p(i))^2 < (n-1)*n*(n+1)/6. 0
1, 3, 11, 57, 360, 2428, 19692, 178096, 1814400, 19748160, 237351468, 3091307829, 43589145600, 650470873262, 10415387654044, 177171175431551, 3201186852864000, 60647963017860105, 1213361365706836584, 25488014447816087399, 562000363888803840000 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..22.

FORMULA

a(n) = A000142(n)/2 - A056876(n)/2. - Alois P. Heinz, May 07 2013

CROSSREFS

Sequence in context: A094611 A052442 A217034 * A188458 A212435 A001586

Adjacent sequences:  A180109 A180110 A180111 * A180113 A180114 A180115

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 10 2010

EXTENSIONS

a(16)-a(19) from Robert Gerbicz, Nov 27 2010

a(20)-a(22) from Alois P. Heinz, May 07 2013

STATUS

approved

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Last modified November 12 05:52 EST 2019. Contains 329051 sequences. (Running on oeis4.)