|
%I #4 Dec 25 2014 07:59:01
%S 20,483,8694,112877,1100210,8528422,54926890,303382053,1471499970,
%T 6383377435,25130419118,90859574359,304675148476,955390407363,
%U 2821209579406,7892066379909,21022079637900,53557533613173
%N Number of nX7 nonnegative integer arrays with upper left 0 and lower right n+7-5 and value increasing by 0 or 1 with every step right or down
%C Column 7 of A252976
%H R. H. Hardin, <a href="/A252975/b252975.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = (491/510909421717094400)*n^21 + (491/4054836680294400)*n^20 + (31237/4561691265331200)*n^19 + (16931/72754246656000)*n^18 + (6860417/1280474741145600)*n^17 + (5620079/62768369664000)*n^16 + (28238557/24715045555200)*n^15 + (460147/39626496000)*n^14 + (1994012479/20542375526400)*n^13 + (9803403773/14485008384000)*n^12 + (2842330237/724250419200)*n^11 + (22704330871/1207084032000)*n^10 + (117780405261823/1581762915532800)*n^9 + (1372309011587/5706215424000)*n^8 + (17399771450683/28245766348800)*n^7 + (29498769372031/23538138624000)*n^6 + (57797311549729/26676557107200)*n^5 + (6071375333369/2020951296000)*n^4 + (7008309815167/1119943843200)*n^3 + (375662307017/83805321600)*n^2 + (152121493/25865840)*n - 4
%e Some solutions for n=4
%e ..0..1..2..3..3..3..4....0..1..1..2..2..3..4....0..0..1..2..3..3..3
%e ..1..2..2..3..3..3..4....1..1..2..3..3..4..5....1..1..1..2..3..4..4
%e ..2..2..2..3..3..4..5....2..2..3..3..4..5..6....1..1..2..2..3..4..5
%e ..2..3..3..4..4..5..6....2..3..4..4..5..6..6....1..1..2..3..4..5..6
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 25 2014
| 