cp's OEIS Frontend

A252826 Number of nX6 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

%I A252826 #6 Jul 23 2025 13:40:38
%S A252826 26,339,3891,36292,271846,1679072,8807722,40232545,163307844,
%T A252826 598768118,2009666884,6242686351,18111918515,49456857086,127928520595,
%U A252826 315195592486,743219906659,1684034391078,3679765581966,7778027858175,15947032415637
%N A252826 Number of nX6 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.
%C A252826 Column 6 of A252828
%H A252826 R. H. Hardin, <a href="/A252826/b252826.txt">Table of n, a(n) for n = 1..210</a>
%F A252826 Empirical: a(n) = (883/1600593426432000)*n^18 + (883/16167610368000)*n^17 + (148963/62768369664000)*n^16 + (6599/108972864000)*n^15 + (8020459/7846046208000)*n^14 + (3062099/249080832000)*n^13 + (813736283/7242504192000)*n^12 + (166116079/201180672000)*n^11 + (1097726573/219469824000)*n^10 + (598115773/24385536000)*n^9 + (466445792503/4828336128000)*n^8 + (272090281/870912000)*n^7 + (19554578278049/23538138624000)*n^6 + (1173600978721/653837184000)*n^5 + (4602055984369/1307674368000)*n^4 + (98334957191/18162144000)*n^3 + (263932729939/30875644800)*n^2 + (3637273/816816)*n + 1
%e A252826 Some solutions for n=4
%e A252826 ..0..1..2..3..3..3....0..1..2..3..3..3....0..0..1..2..2..2....0..1..1..1..1..2
%e A252826 ..1..2..3..3..4..4....1..1..2..3..3..3....1..1..2..2..2..3....0..1..2..2..2..3
%e A252826 ..1..2..3..4..4..4....1..2..3..3..4..4....1..1..2..3..3..4....1..2..2..3..3..4
%e A252826 ..2..3..4..5..5..5....2..3..3..4..5..5....1..2..3..4..4..5....2..2..3..4..4..5
%K A252826 nonn
%O A252826 1,1
%A A252826 _R. H. Hardin_, Dec 22 2014