A185471 Number of (n+2)X5 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order.
13659, 76309, 308692, 1043186, 3097348, 8297059, 20411234, 46732687, 100636591, 205574323, 401123377, 751921908, 1360579387, 2385984676, 4068843506, 6766785098, 11002001311, 17525142877, 27400120766, 42115574722, 63730107482
Offset: 1
Keywords
Examples
Some solutions for 4X5 ..0..0..0..1..2....0..0..0..0..0....0..0..0..0..2....0..0..0..1..1 ..0..0..1..1..2....0..0..1..2..2....0..0..0..2..2....0..0..0..1..2 ..0..1..1..2..0....1..1..2..1..1....0..0..1..0..1....0..1..1..1..2 ..2..1..2..0..2....2..2..2..1..2....1..2..2..1..1....1..1..2..2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Formula
Empirical: a(n) = (1/444787200)*n^13
+ (107/479001600)*n^12
+ (11/1088640)*n^11
+ (3623/6220800)*n^10
+ (78227/3628800)*n^9
+ (6420917/14515200)*n^8
+ (148481/27216)*n^7
+ (1861160843/43545600)*n^6
+ (4966108109/21772800)*n^5
+ (1448539279/1555200)*n^4
+ (3663351401/1330560)*n^3
+ (2013261953/415800)*n^2
+ (15650889/3640)*n
+ 556
Comments