OFFSET
1,1
REFERENCES
Brualdi, Richard A. and Ryser, Herbert J., Combinatorial Matrix Theory, Cambridge NY (1991), Chapter 7.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Seok-Zun Song et al., Extremes of permanents of (0,1)-matrices, Lin. Algebra and its Applic. 373 (2003), pp. 197-210.
FORMULA
a(n) = (n+5)*a(n-1) + (n-1)*a(n-2), a(1)=6, a(2)=43
G.f.: -1+hypergeom([1,7],[],x/(x+1))/(x+1) - Mark van Hoeij, Nov 07 2011
E.g.f.: -1 + exp(-x)/(1-x)^7. - Vaclav Kotesovec, Oct 21 2012
a(n) ~ n!*n^6/(720*e). - Vaclav Kotesovec, Oct 21 2012
MAPLE
MATHEMATICA
Rest[CoefficientList[Series[E^(-x)/(1-x)^7, {x, 0, 20}], x]*Range[0, 20]!] (* Vaclav Kotesovec, Oct 21 2012 *)
PROG
(PARI) x='x+O('x^66); Vec(serlaplace(-1+exp(-x)/(1-x)^7)) \\ Joerg Arndt, May 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jaap Spies, Dec 13 2003
EXTENSIONS
Corrected by Jaap Spies, Jan 26 2004
STATUS
approved