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A179610 Eight white kings and one red king on a 3 X 3 chessboard. G.f.: 1/(1-3*x-5*x^2+4*x^3). 3
1, 3, 14, 53, 217, 860, 3453, 13791, 55198, 220737, 883037, 3532004, 14128249, 56512619, 226051086, 904203357, 3616815025, 14467257516, 57869034245, 231476130215, 925904531806, 3703618109513, 14814472466709, 59257889820468 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The a(n) represent the number of n-move routes of a fairy chess piece starting in a given corner square (m = 1, 3, 7 or 9) on a 3 X 3 chessboard. This fairy chess piece behaves like a king on the eight side and corner squares but on the central square the king goes crazy and turns into a red king, see A179596.

The sequence above corresponds to 4 red king vectors, i.e. A[5] vectors, with decimal [binary] values 85 [0,0,1,0,1,0,1,0,1], 277 [1,0,0,0,1,0,1,0,1], 337 [1,0,1,0,1,0,0,0,1] and 340 [1,0,1,0,1,0,1,0,0].

Convolution of (-4)^n and F(n+1) with F = A000045.

LINKS

Table of n, a(n) for n=0..23.

FORMULA

G.f.: = 1/((x^2-x-1)*(4*x-1)).

a(n) = 3*a(n-1)+5*a(n-2)-4*a(n-3) with a(1)=1, a(2)=3 and a(3)=14.

a(n) = (1/95)*(5*2^(2*n+4)-(11-2*phi)*phi^(-n-1)-(9+2*phi)*(1-phi)^(-n-1)) with phi = (1+sqrt(5))/2, with A001622 = phi.

a(n) = (-1)^n*sum((-4)^m*F(n+1-m),m=0..n).

MAPLE

with(LinearAlgebra): nmax:=23; m:=1; A[1]:= [0, 1, 0, 1, 1, 0, 0, 0, 0]: A[2]:= [1, 0, 1, 1, 1, 1, 0, 0, 0]: A[3]:= [0, 1, 0, 0, 1, 1, 0, 0, 0]: A[4]:=[1, 1, 0, 0, 1, 0, 1, 1, 0]: A[5]:= [1, 0, 0, 0, 1, 0, 1, 0, 1]: A[6]:= [0, 1, 1, 0, 1, 0, 0, 1, 1]: A[7]:= [0, 0, 0, 1, 1, 0, 0, 1, 0]: A[8]:= [0, 0, 0, 1, 1, 1, 1, 0, 1]: A[9]:= [0, 0, 0, 0, 1, 1, 0, 1, 0]: A:=Matrix([A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[8], A[9]]): for n from 0 to nmax do B(n):=A^n: a(n):= add(B(n)[m, k], k=1..9): od: seq(a(n), n=0..nmax);

CROSSREFS

Sequence in context: A017946 A083424 A099487 * A166680 A104191 A318125

Adjacent sequences:  A179607 A179608 A179609 * A179611 A179612 A179613

KEYWORD

easy,nonn

AUTHOR

Johannes W. Meijer, Jul 28 2010, revised Aug 15 2010

STATUS

approved

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Last modified November 15 09:36 EST 2018. Contains 317232 sequences. (Running on oeis4.)