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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A187509 Number of 4-step S, E, and NW-moving king's tours on an n X n board summed over all starting positions 1
 0, 2, 36, 115, 236, 399, 604, 851, 1140, 1471, 1844, 2259, 2716, 3215, 3756, 4339, 4964, 5631, 6340, 7091, 7884, 8719, 9596, 10515, 11476, 12479, 13524, 14611, 15740, 16911, 18124, 19379, 20676, 22015, 23396, 24819, 26284, 27791, 29340, 30931, 32564, 34239 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row 4 of A187507 LINKS R. H. Hardin, Table of n, a(n) for n = 1..50 FORMULA Empirical: a(n) = 21*n^2 - 68*n + 51 for n>2. Empirical G.f.: x^2*(2+30*x+13*x^2-3*x^3)/(1-x)^3. [Colin Barker, Jan 22 2012] EXAMPLE Some solutions for 4X4 ..0..0..0..0....0..0..0..0....0..4..2..0....0..4..0..0....0..0..0..0 ..1..2..3..0....0..1..0..0....0..0..3..1....0..2..3..0....0..1..2..0 ..0..0..4..0....0..2..3..0....0..0..0..0....0..0..1..0....0..0..3..4 ..0..0..0..0....0..0..4..0....0..0..0..0....0..0..0..0....0..0..0..0 CROSSREFS Sequence in context: A258356 A145450 A196558 * A134785 A143745 A199944 Adjacent sequences:  A187506 A187507 A187508 * A187510 A187511 A187512 KEYWORD nonn AUTHOR R. H. Hardin Mar 10 2011 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 December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)