OFFSET
0,5
COMMENTS
Number of ways 5 dominoes can be placed on an n X n chessboard.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: 4*(2*x^11 -6*x^10 +17*x^9 -559*x^8 +3298*x^7 -5840*x^6 -8668*x^5 +55222*x^4 -105932*x^3 -148674*x^2 -29933*x -847)*x^4 / (x-1)^11.
a(n) = (4*n^10 -20*n^9 -100*n^8 +640*n^7 +635*n^6 -7589*n^5 +2370*n^4 +39275*n^3 -35789*n^2 -74246*n +86580)/15 for n>=5, a(4) = 3388, a(n) = 0 for n<=3.
MAPLE
a:= n-> `if`(n<5, [0$4, 3388][n+1], ((((((((((4*n-20)*n-100)*n+640)
*n+635)*n-7589)*n+2370)*n+39275)*n-35789)*n-74246)*n+86580)/15):
seq(a(n), n=0..40);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jun 01 2014
STATUS
approved