This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A252974 #6 Jul 23 2025 13:49:30 %S A252974 10,192,2859,30802,248182,1592348,8528422,39423196,161160206, %T A252974 593478797,1997447386,6215980425,18056320047,49345966862,127715626611, %U A252974 314800577783,742509146839,1682790560239,3677643193138,7774488966837,15941255148133 %N A252974 Number of nX6 nonnegative integer arrays with upper left 0 and lower right n+6-5 and value increasing by 0 or 1 with every step right or down. %C A252974 Column 6 of A252976 %H A252974 R. H. Hardin, <a href="/A252974/b252974.txt">Table of n, a(n) for n = 1..210</a> %F A252974 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 + (813101243/7242504192000)*n^12 + (165163519/201180672000)*n^11 + (1074230093/219469824000)*n^10 + (564482173/24385536000)*n^9 + (410608176823/4828336128000)*n^8 + (212043001/870912000)*n^7 + (12296690400809/23538138624000)*n^6 + (525004330021/653837184000)*n^5 + (1880413300609/1307674368000)*n^4 + (10237127057/6054048000)*n^3 + (183696263083/30875644800)*n^2 + (15176011/12252240)*n - 2 %e A252974 Some solutions for n=4 %e A252974 ..0..1..1..2..3..4....0..1..2..2..3..4....0..1..1..2..3..3....0..1..1..2..3..3 %e A252974 ..0..1..2..3..4..4....1..2..3..3..3..4....0..1..2..2..3..4....1..1..2..2..3..3 %e A252974 ..1..2..3..4..4..4....2..3..3..3..3..4....0..1..2..3..4..5....1..2..2..3..3..4 %e A252974 ..2..3..3..4..4..5....3..3..3..4..4..5....1..2..3..4..4..5....2..2..2..3..4..5 %K A252974 nonn %O A252974 1,1 %A A252974 _R. H. Hardin_, Dec 25 2014