A220012 Number of 3Xn arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 3Xn array

10, 20, 109, 479, 1735, 5686, 17525, 51891, 148887, 415328, 1127801, 2983759, 7698970, 19398768, 47793075, 115286948, 272626057, 632754218, 1442939429, 3236143029, 7144195995, 15536960940, 33309810566, 70444500191, 147041223854

Offset

1,1

Comments

Row 3 of A220010

Links

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

Formula

Empirical: a(n) = (1/33607621760550469632000000)*n^26 - (29/5170403347776995328000000)*n^25 + (31/62044840173323943936000)*n^24 - (109/5442529839765258240000)*n^23 - (25027/67440043666656460800000)*n^22 + (46357/454141708192972800000)*n^21 - (483869/72128388948295680000)*n^20 + (24247537/102181884343418880000)*n^19 - (985474829/322679634768691200000)*n^18 - (34068475489/215119756512460800000)*n^17 + (479709089549/41758540970065920000)*n^16 - (138518494001/356910606581760000)*n^15 + (21512251671251281/2714305163054284800000)*n^14 - (10365455888214533/139195136566886400000)*n^13 - (47137945089864631/41758540970065920000)*n^12 + (38939213107138853/632705166213120000)*n^11 - (108277075670437250453/80669908692172800000)*n^10 + (82547306222649133721/4481661594009600000)*n^9 - (12081064949487162568993/76636413257564160000)*n^8 + (6497603208990962823589/12772735542927360000)*n^7 + (4044430533533808049709153/585417045717504000000)*n^6 - (39959078269525038081247/320952327696000000)*n^5 + (224843841913348330527047/220009674044160000)*n^4 - (2422774423532199558167/479508263942400)*n^3 + (14278279432468388566987/964724959598400)*n^2 - (36099811878753947/1673196525)*n + 7795656 for n>13

Example

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

Crossrefs

Sequence in context: A260743 A161999 A086069 * A154330 A006993 A327971

Adjacent sequences: A220009 A220010 A220011 * A220013 A220014 A220015

Keyword

nonn

Author

R. H. Hardin Dec 03 2012

Status

approved