OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
D. E. Knuth, Nonattacking kings on a chessboard, 1994.
Vaclav Kotesovec, Number of ways of placing non-attacking queens and kings on boards of various sizes [Vaclav Kotesovec, Feb 06 2010]
H. S. Wilf, The problem of the kings, Elec. J. Combin. 2, 1995.
Index entries for linear recurrences with constant coefficients, signature (19, -148, 604, -1364, 1644, -928, 192).
FORMULA
G.f.: (1+13x-52x^2-20x^3+60x^4-20x^5)/((1-3x)(1-4x)^2(1-4x+2x^2)^2).
Explicit formula: (231n-2377)*4^n - 384*3^n + (1953*sqrt(2)/2+1381+(35*sqrt(2)+99/2)*n)*(2+sqrt(2))^n + (1381-1953*sqrt(2)/2+(99/2-35*sqrt(2))*n)*(2-sqrt(2))^n. - Vaclav Kotesovec, Feb 06 2010
PROG
(PARI) a(n)=polcoeff((1+13*x-52*x^2-20*x^3+60*x^4-20*x^5)/((1-3*x)*(1-4*x)^2*(1-4*x+2*x^2)^2)+x*O(x^n), n)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), May 22 2001
EXTENSIONS
Corrected data by Vincenzo Librandi, Oct 12 2011
STATUS
approved