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A188498 Number of permutations p on the set [n] with the properties that abs(p(i)-i) <= 3 for all i, p(1) <= 2, and p(j) >= 2 for j=3,4. 3
0, 1, 2, 3, 8, 30, 102, 308, 905, 2744, 8473, 26112, 79924, 244204, 747160, 2288521, 7009458, 21461803, 65704200, 201162258, 615922714, 1885853660, 5774072225, 17678809840, 54128358209, 165728860112, 507424764216, 1553620027784, 4756831354752 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n) is also the permanent of the n-by-n matrix that has ones on its diagonal, ones on its three superdiagonals (with the exception of zeroes in the (1,3) and (1,4)-entries), ones on its three subdiagonals (with the exception of zeroes in the (3,1) and (4,1)-entries), and is zero elsewhere.

This is row 13 of Klove's Table 3.

LINKS

Table of n, a(n) for n=0..28.

Torleiv Klove, Spheres of Permutations under the Infinity Norm - Permutations with limited displacement. Reports in Informatics, Department of Informatics, University of Bergen, Norway, no. 376, November 2008.

FORMULA

Contribution from Nathaniel Johnston, Apr 11 2011 (Start):

a(n) = A188497(n+1) - A188494(n).

a(n) = A002526(n-1) + A002526(n-2).

(End)

G.f.: -(x^10+2*x^9+x^8 -2*x^6-2*x^5-2*x^4 -3*x^3+x) / (x^14+2*x^13+2*x^11 +4*x^10-2*x^9-10*x^8 -16*x^7-2*x^6+8*x^5 +10*x^4+2*x^2+2*x-1).

MAPLE

with(LinearAlgebra):

A188498:= n-> `if` (n=0, 0, Permanent (Matrix (n, (i, j)->

              `if` (abs(j-i)<4 and [i, j]<>[1, 3] and [i, j]<>[1, 4] and [i, j]<>[3, 1] and [i, j]<>[4, 1], 1, 0)))):

seq (A188498(n), n=0..20);

CROSSREFS

Sequence in context: A186927 A177010 A004106 * A012886 A078918 A054104

Adjacent sequences:  A188495 A188496 A188497 * A188499 A188500 A188501

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Apr 01 2011

EXTENSIONS

Name and comments edited, and a(12) - a(28) from Nathaniel Johnston, Apr 11 2011

STATUS

approved

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Last modified October 21 09:39 EDT 2014. Contains 248377 sequences.