A227556 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order

11, 81, 585, 3939, 23940, 130231, 635595, 2807533, 11342619, 42338997, 147335893, 481696118, 1489318226, 4378976416, 12302356074, 33158604442, 86042468013, 215601894342, 523073738362, 1231552044657, 2819779172382, 6289922485458

Offset

1,1

Comments

Column 4 of A227558

Links

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

Formula

Empirical: a(n) = (1/39895087560007680000)*n^23 - (1/578189674782720000)*n^22 + (31/157688093122560000)*n^21 - (43/4505374089216000)*n^20 + (11/21332263680000)*n^19 - (10573/592812380160000)*n^18 + (2466337/4149686661120000)*n^17 - (360889/24409921536000)*n^16 + (14848109/44381675520000)*n^15 - (60304879/9963233280000)*n^14 + (74438290021/767168962560000)*n^13 - (3037062851/2360519884800)*n^12 + (1208999658479/81366405120000)*n^11 - (8787007618057/61024803840000)*n^10 + (276658611991/231154560000)*n^9 - (58139339838841/6974263296000)*n^8 + (3604676599939619/74101547520000)*n^7 - (17135686774664321/74101547520000)*n^6 + (16296634954448087/18665730720000)*n^5 - (2453303492285163517/985550582016000)*n^4 + (752720185790708953/150570227808000)*n^3 - (2634333865637083/430200650880)*n^2 + (1796305131851/594914320)*n + 933 for n>5

Example

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

Crossrefs

Sequence in context: A211557 A333061 A055429 * A181989 A199557 A003730

Adjacent sequences: A227553 A227554 A227555 * A227557 A227558 A227559

Keyword

nonn

Author

R. H. Hardin Jul 16 2013

Status

approved