A211365 - OEIS

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A211365

Array read by antidiagonals: T(m,n) = Sum(1<=i<=m) i * (2m+n-1-i)!

1, 2, 10, 6, 36, 186, 24, 168, 1032, 6936, 120, 960, 6840, 53040, 462120, 720, 6480, 52560, 461520, 4499280, 48453840, 5040, 50400, 458640, 4495680, 48449520, 571404960, 7321381200, 40320, 443520, 4475520, 48424320, 571374720, 7321345920

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Index numbers (compare A055089) of permutations like (2,4,6,...,1,3,5...).

LINKS

Tilman Piesk, Table of n, a(n) for n = 1..2016

Tilman Piesk, Arrays of permutations (Wikiversity)

EXAMPLE

T(3,2) = Sum( 1 <= i <= 3 ) [ i * (7-i)! ]

= 1*(7-1)! + 2*(7-2)! + 3*(7-3)!

= 1*720 + 2*120 + 3*24