A223721 - OEIS

%I #8 Oct 03 2025 22:14:08

%S 46,2116,46613,608855,5537147,38566854,218619076,1051051942,

%T 4413826871,16548850432,56334327215,176427795883,513754867486,

%U 1403147317562,3620163947216,8876634938318,20791393840502,46723393566999

%N Number of nX4 0..2 arrays with rows, antidiagonals and columns unimodal.

%C Column 4 of A223725

%H R. H. Hardin, <a href="/A223721/b223721.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (456419/5230697472000)*n^16 + (299363/186810624000)*n^15 + (8437981/261534873600)*n^14 + (678959/1868106240)*n^13 + (91942579/28740096000)*n^12 + (161673031/7185024000)*n^11 + (203867119/1828915200)*n^10 + (37055/81648)*n^9 + (59612358509/36578304000)*n^8 + (2850286193/1306368000)*n^7 + (7237625987/718502400)*n^6 + (573765127/143700480)*n^5 - (109277252779/4036032000)*n^4 + (59181202013/216216000)*n^3 - (12927784033/16816800)*n^2 + (36815651/36036)*n - 470 for n>2

%e Some solutions for n=3

%e ..0..0..1..2....1..2..2..1....1..1..0..0....1..2..0..0....0..0..1..2

%e ..0..1..2..2....0..2..2..2....1..1..1..0....1..2..2..1....0..1..2..2

%e ..0..1..2..2....0..0..2..0....0..1..2..0....2..1..1..0....2..1..1..0

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 26 2013