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

1,1

Comments

Row 6 of A266470.

Links

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

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

Example

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

Crossrefs

Cf. A266470.

Sequence in context: A303091 A333887 A179599 * A297677 A287860 A347814

Adjacent sequences: A266470 A266471 A266472 * A266474 A266475 A266476

Keyword

nonn

Author

R. H. Hardin, Dec 29 2015

Status

approved