A266473 Number of 6Xn binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

7, 29, 147, 794, 4074, 18808, 77320, 285494, 959672, 2975483, 8605341, 23428725, 60497931, 149066593, 352233950, 801471439, 1762213254, 3755124007, 7774777259, 15675004492, 30833594755, 59276323572, 111542905766, 205731574732

Offset: 1

Author

R. H. Hardin, Dec 29 2015

Keywords

• nonn

Comments

Row 6 of A266470.

Examples

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

Links

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

Crossrefs

Cf. A266470.

Formula

Empirical: a(n) = (1/121645100408832000)*n^19 + (1/914624815104000)*n^18 + (37/533531142144000)*n^17 + (89/31384184832000)*n^16 + (1039/12553673932800)*n^15 + (116807/62768369664000)*n^14 + (3153461/94152554496000)*n^13 + (511019/1034643456000)*n^12 + (57504877/9656672256000)*n^11 + (48689987/877879296000)*n^10 + (475429693/1207084032000)*n^9 + (2471183497/1207084032000)*n^8 + (117295069721/23538138624000)*n^7 + (79279038437/3362591232000)*n^6 + (2282457077/12108096000)*n^5 - (6773798653/40864824000)*n^4 + (20107095509/9648639000)*n^3 - (10497092849/7718911200)*n^2 + (607842269/116396280)*n + 1