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A227254 Number of nX4 binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically nondecreasing rows and columns, for some larger (n+1)X5 binary array with rows and columns of the latter in lexicographically nondecreasing order 1
7, 23, 134, 813, 4578, 22659, 98821, 388681, 1403516, 4714206, 14875044, 44432556, 126415358, 344289685, 901306978, 2275929413, 5559947847, 13174033412, 30343762095, 68072517741, 148997133853, 318682656840, 666983823620 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A227256

LINKS

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

FORMULA

Empirical: a(n) = (1/1615751046180311040000)*n^23 - (1/17562511371525120000)*n^22 + (47/6386367771463680000)*n^21 - (61/130334036152320000)*n^20 + (137/4607768954880000)*n^19 - (3013/2286562037760000)*n^18 + (8844359/168062309775360000)*n^17 - (312287/190115735040000)*n^16 + (886379059/19772036444160000)*n^15 - (1420704487/1412288317440000)*n^14 + (203799917239/10356780994560000)*n^13 - (12399719441/37936926720000)*n^12 + (1063351164833/224682232320000)*n^11 - (1154985638557243/19772036444160000)*n^10 + (275422039495271/449364464640000)*n^9 - (7500326892522067/1412288317440000)*n^8 + (9240597952126787/250092722880000)*n^7 - (13880538229405699/71455063680000)*n^6 + (137736482787968773/205323037920000)*n^5 - (360812024910147697/568586874240000)*n^4 - (1806440435059302017/225855341712000)*n^3 + (164721791470756099/3226504881600)*n^2 - (12692795286877/89237148)*n + 166461 for n>8

EXAMPLE

Some solutions for n=4

..1..1..1..0....1..1..1..1....1..1..1..1....1..0..0..1....1..1..1..1

..1..1..0..1....1..0..1..1....1..0..0..0....0..1..1..1....1..0..0..1

..1..1..1..0....0..1..1..0....0..1..1..0....0..1..0..0....0..1..1..1

..1..0..0..0....1..1..1..0....1..1..1..1....1..1..0..1....0..1..0..0

CROSSREFS

Sequence in context: A064639 A064638 A082021 * A080082 A158954 A056205

Adjacent sequences:  A227251 A227252 A227253 * A227255 A227256 A227257

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 04 2013

STATUS

approved

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Last modified September 17 03:42 EDT 2021. Contains 347478 sequences. (Running on oeis4.)