cp's OEIS Frontend

A252818 Number of n X 6 nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

%I A252818 #6 Nov 03 2022 21:46:15
%S A252818 16,147,1032,5490,23664,86724,279300,809349,2147638,5289321,12219498,
%T A252818 26705926,55598468,110890224,212893984,395014703,710759820,1243830839,
%U A252818 2122388828,3538891338,5777267504,9249641452,14545342212,22495562705
%N A252818 Number of n X 6 nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.
%C A252818 Column 6 of A252820.
%H A252818 R. H. Hardin, <a href="/A252818/b252818.txt">Table of n, a(n) for n = 1..210</a>
%F A252818 Empirical: a(n) = (1/11404800)*n^12 + (1/211200)*n^11 + (37/345600)*n^10 + (143/103680)*n^9 + (27977/2419200)*n^8 + (83399/1209600)*n^7 + (319693/1036800)*n^6 + (34283/34560)*n^5 + (59941/28800)*n^4 + (482543/129600)*n^3 + (720359/277200)*n^2 + (44551/13860)*n + 3.
%e A252818 Some solutions for n=4
%e A252818 ..0..1..2..3..4..5....0..1..2..3..4..5....0..1..2..3..3..4....0..1..2..2..3..4
%e A252818 ..1..2..2..3..4..5....1..2..3..4..4..5....1..2..3..4..4..5....1..2..2..2..3..4
%e A252818 ..2..3..3..3..4..5....2..2..3..4..5..5....1..2..3..4..5..5....2..3..3..3..4..5
%e A252818 ..3..3..3..4..5..6....3..3..4..5..5..6....1..2..3..4..5..6....3..4..4..4..5..6
%Y A252818 Cf. A252820.
%K A252818 nonn
%O A252818 1,1
%A A252818 _R. H. Hardin_, Dec 22 2014