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!)
 A140518 Number of simple paths from corner to corner of an n X n grid with king-moves allowed. 6
 1, 5, 235, 96371, 447544629, 22132498074021, 10621309947362277575, 50819542770311581606906543, 2460791237088492025876789478191411, 1207644919895971862319430895789323709778193, 5996262208084349429209429097224046573095272337986011 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This graph is the "strong product" of P_n with P_n, where P_n is a path of length n. Sequence A007764 is what we get when we restrict ourselves to rook moves of unit length. Computed using ZDDs (ZDD = "reduced, order, zero-suppressed binary decision diagram"). REFERENCES Donald E. Knuth, The Art of Computer Programming, Vol. 4, fascicle 1, section 7.1.4, p. 117, Addison-Wesley, 2009. LINKS EXAMPLE For example, when n=8 this is the number of ways to move a king from a1 to h8 without occupying any cell twice. CROSSREFS Main diagonal of A329118. Cf. A140519, A158651, A234622, A007764, A038496. Cf. A220638 (Hosoya index). Sequence in context: A265957 A137085 A153025 * A269551 A200962 A270052 Adjacent sequences:  A140515 A140516 A140517 * A140519 A140520 A140521 KEYWORD nonn,walk AUTHOR Don Knuth, Jul 26 2008 EXTENSIONS a(9)-a(11) from Andrew Howroyd, Apr 07 2016 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 August 11 06:25 EDT 2020. Contains 336422 sequences. (Running on oeis4.)