|
%I #7 Jul 04 2013 06:46:35
%S 7,23,134,813,4578,22659,98821,388681,1403516,4714206,14875044,
%T 44432556,126415358,344289685,901306978,2275929413,5559947847,
%U 13174033412,30343762095,68072517741,148997133853,318682656840,666983823620
%N 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
%C Column 4 of A227256
%H R. H. Hardin, <a href="/A227254/b227254.txt">Table of n, a(n) for n = 1..210</a>
%F 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
%e Some solutions for n=4
%e ..1..1..1..0....1..1..1..1....1..1..1..1....1..0..0..1....1..1..1..1
%e ..1..1..0..1....1..0..1..1....1..0..0..0....0..1..1..1....1..0..0..1
%e ..1..1..1..0....0..1..1..0....0..1..1..0....0..1..0..0....0..1..1..1
%e ..1..0..0..0....1..1..1..0....1..1..1..1....1..1..0..1....0..1..0..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Jul 04 2013
| 