The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A221246 Number of 2 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor. 1
 0, 9, 50, 484, 3864, 32400, 267264, 2214144, 18316800, 151585344, 1254325824, 10379534400, 85889605824, 710729930304, 5881230244800, 48666696727104, 402712880117184, 3332415765326400, 27575464553486784, 228184686537228864 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row 2 of A221245. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 9*a(n-1) - 54*a(n-3) + 36*a(n-4) for n>5. Empirical g.f.: x^2*(9 - 31*x + 34*x^2 - 6*x^3) / ((1 - 9*x + 6*x^2)*(1 - 6*x^2)). - Colin Barker, Aug 04 2018 EXAMPLE Some solutions for n=3:   1 3 1   0 3 0   2 2 0   0 4 2   0 2 0   1 4 1   0 2 2   0 1 0   0 1 2   0 2 0   0 0 0   1 2 1   0 0 0   0 2 0 CROSSREFS Cf. A221245. Sequence in context: A188210 A308646 A338510 * A002462 A210061 A034814 Adjacent sequences:  A221243 A221244 A221245 * A221247 A221248 A221249 KEYWORD nonn AUTHOR R. H. Hardin, Jan 06 2013 STATUS approved

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

Last modified May 24 03:38 EDT 2022. Contains 354005 sequences. (Running on oeis4.)