The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A007786 Number of nonintersecting rook paths joining opposite corners of 4 X n board. 8
 1, 8, 38, 184, 976, 5382, 29739, 163496, 896476, 4913258, 26932712, 147657866, 809563548, 4438573234, 24335048679, 133419610132, 731487691902, 4010463268476, 21987818897998, 120550710615560, 660932932108467 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES Netnews group rec.puzzles, Frequently Asked Questions (FAQ) file. (Science Section). LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 F. Faase, Results from the counting program F. Faase, Rook path problem D. G. Radcliffe, N. J. A. Sloane, C. Cole, J. Gillogly, & D. Dodson, Emails, 1994 Index entries for linear recurrences with constant coefficients, signature (12,-54,124,-133,-16,175,-94,-69,40,12,-4,-1). FORMULA a(n) = 12*a(n - 1) - 54*a(n - 2) + 124*a(n - 3) - 133*a(n - 4) - 16*a(n - 5) + 175*a(n - 6) - 94*a(n - 7) - 69*a(n - 8) + 40*a(n - 9) + 12*a(n - 10) - 4*a(n - 11) - a(n - 12). G.f.: x*(x^10-15*x^8+6*x^7+50*x^6-26*x^5-39*x^4+36*x^3-4*x^2-4*x+1) / ((x^6+2*x^5-9*x^4-5*x^3+15*x^2-8*x+1)*(x^6+2*x^5-7*x^4-3*x^3+7*x^2-4*x+1)). [Colin Barker, Nov 24 2012] MATHEMATICA LinearRecurrence[{12, -54, 124, -133, -16, 175, -94, -69, 40, 12, -4, -1}, {1, 8, 38, 184, 976, 5382, 29739, 163496, 896476, 4913258, 26932712, 147657866}, 30] (* Harvey P. Dale, Jun 27 2012 *) CROSSREFS Row 4 of A064298. Cf. A006192, A007764, A007787. Sequence in context: A197338 A214931 A229366 * A026662 A196074 A329172 Adjacent sequences:  A007783 A007784 A007785 * A007787 A007788 A007789 KEYWORD nonn,easy,nice,walk AUTHOR Heiner Marxen EXTENSIONS Formula and more terms from Vladeta Jovovic, Mar 20 2000 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.

Last modified October 22 22:22 EDT 2020. Contains 337962 sequences. (Running on oeis4.)