A226989 Number of nX3 0..4 arrays of sums of 2X2 subblocks of some (n+1)X4 binary array with rows and columns of the latter in lexicographically nondecreasing order

15, 120, 608, 2820, 11325, 40431, 130479, 385529, 1054857, 2699060, 6512038, 14918723, 32643565, 68558024, 138781999, 271754453, 516328629, 954420655, 1720389300, 3030202067, 5224614220, 8832133194, 14659559110, 23920501241

Offset

1,1

Comments

Column 3 of A226992

Links

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

Formula

Empirical: a(n) = (1/1307674368000)*n^15 + (1/10897286400)*n^14 + (47/9340531200)*n^13 + (79/479001600)*n^12 + (2341/653184000)*n^11 + (2369/43545600)*n^10 + (136267/228614400)*n^9 + (1466509/304819200)*n^8 + (37910533/1306368000)*n^7 + (1168211/8709120)*n^6 + (362956849/718502400)*n^5 + (181454291/119750400)*n^4 + (8088745109/2270268000)*n^3 + (480216697/75675600)*n^2 + (6472/819)*n + 5 for n>7

Example

Some solutions for n=4
..1..2..2....0..0..1....0..1..2....0..1..2....1..2..2....0..0..0....0..0..1
..2..2..1....0..1..3....0..2..4....1..3..3....2..2..1....0..1..2....0..1..2
..3..2..1....1..3..4....2..2..2....2..3..4....3..3..3....1..2..3....1..2..1
..4..4..3....3..3..2....4..2..0....3..2..3....4..4..4....2..2..2....3..2..0

Crossrefs

Sequence in context: A196506 A027484 A185542 * A126898 A162635 A247612

Adjacent sequences: A226986 A226987 A226988 * A226990 A226991 A226992

Keyword

nonn

Author

R. H. Hardin Jun 25 2013

Status

approved