login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A025603 Number of n-move queen paths on 8x8 board from given corner to any square. 1
1, 21, 465, 10565, 241697, 5539893, 127041105, 2913686981, 66827609633, 1532754884725, 35155272163473, 806321934125125, 18493816732267425, 424174583966543669, 9728877611505065297, 223141752041771533125, 5117984163043834408865, 117386198048567829057141 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..225

FORMULA

G.f.: -(3*x-1) *(16*x^3-4*x^2-5*x+1) *(112*x^4-124*x^3-8*x^2+11*x-1) / (112896*x^9 -170880*x^8 +29184*x^7 +55636*x^6 -26128*x^5 +79*x^4 +2120*x^3 -482*x^2 +40*x-1). - Alois P. Heinz, Jun 26 2012

MAPLE

b:= proc(n, i, j) option remember;

      `if`(n<0 or i<0 or i>7 or j<0 or j>7, 0, `if`(n=0,

      1, add (add (b(n-1, i+t*r[1], j+t*r[2]), r=[[1, 1],

      [1, -1], [-1, 1], [-1, -1], [0, 1], [0, -1], [1, 0],

      [-1, 0]]), t=1..7)))

    end:

a:= n-> b (n, 7, 7):

seq (a(n), n=0..20);  # Alois P. Heinz, Jun 26 2012

MATHEMATICA

b[n_, i_, j_] := b[n, i, j] = If[n<0 || i<0 || i>7 || j<0 || j>7, 0, If[n == 0, 1, Sum[Sum[b[n-1, i+t*r[[1]], j+t*r[[2]]], {r, {{1, 1}, {1, -1}, {-1, 1}, {-1, -1}, {0, 1}, {0, -1}, {1, 0}, {-1, 0}}}], {t, 1, 7}]]]; a[n_] := b[n, 7, 7]; Table[a[n], {n, 0, 30}] (* Jean-Fran├žois Alcover, May 28 2015, after Alois P. Heinz *)

CROSSREFS

Sequence in context: A126996 A158603 A307600 * A296586 A269922 A006298

Adjacent sequences:  A025600 A025601 A025602 * A025604 A025605 A025606

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 16 06:18 EST 2019. Contains 330016 sequences. (Running on oeis4.)