A227253 Number of nX3 binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically nondecreasing rows and columns, for some larger (n+1)X4 binary array with rows and columns of the latter in lexicographically nondecreasing order

4, 9, 36, 134, 450, 1353, 3722, 9529, 22957, 52447, 114282, 238618, 479284, 929223, 1744166, 3178057, 5634919, 9743313, 16461342, 27222342, 44134038, 70247085, 109912626, 169252849, 256773585, 384153835, 567253826, 827390858, 1192940904

Offset

1,1

Comments

Column 3 of A227256

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (1/9979200)*n^11 - (1/453600)*n^10 + (1/11340)*n^9 - (71/60480)*n^8 + (163/11200)*n^7 - (251/2700)*n^6 + (49501/90720)*n^5 - (319397/181440)*n^4 + (486707/113400)*n^3 + (34133/25200)*n^2 - (238061/6930)*n + 65 for n>3

Example

Some solutions for n=4
..1..1..1....1..1..1....1..1..1....1..0..0....1..1..1....1..1..0....1..0..0
..1..0..0....1..0..0....1..1..0....0..1..1....1..1..0....1..0..1....0..1..1
..0..1..1....0..1..1....1..0..1....0..1..0....1..1..0....1..0..0....1..1..0
..1..1..0....1..1..1....0..0..1....1..1..0....1..0..0....1..0..0....1..1..1

Crossrefs

Sequence in context: A149145 A262473 A001256 * A029997 A118548 A176830

Adjacent sequences: A227250 A227251 A227252 * A227254 A227255 A227256

Keyword

nonn

Author

R. H. Hardin Jul 04 2013

Status

approved