Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%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