cp's OEIS Frontend

A250356 Number of length 7 arrays x(i), i=1..7 with x(i) in i..i+n and no value appearing more than 2 times.

%I A250356 #6 Jul 23 2025 12:20:17
%S A250356 128,1791,12620,59406,214716,644040,1681860,3932472,8409252,16713576,
%T A250356 31259100,55546440,94493292,154825032,245530836,378390360,568576020,
%U A250356 835335912,1202762412,1700651496,2365457820,3241350600,4381375332
%N A250356 Number of length 7 arrays x(i), i=1..7 with x(i) in i..i+n and no value appearing more than 2 times.
%C A250356 Row 7 of A250351
%H A250356 R. H. Hardin, <a href="/A250356/b250356.txt">Table of n, a(n) for n = 1..91</a>
%F A250356 Empirical: a(n) = n^7 + 7*n^6 - 14*n^5 + 105*n^4 + 105*n^3 - 532*n^2 + 1252*n - 744 for n>4
%e A250356 Some solutions for n=4
%e A250356 ..1....1....2....2....2....1....1....0....0....2....4....3....1....0....1....3
%e A250356 ..3....3....1....1....3....2....4....1....4....1....2....2....3....5....4....2
%e A250356 ..2....2....2....5....4....3....6....6....4....4....2....4....5....2....6....6
%e A250356 ..3....4....6....7....7....7....7....5....6....6....7....6....5....3....6....4
%e A250356 ..6....4....4....5....4....6....6....6....5....6....4....5....6....7....5....5
%e A250356 ..5....9....6....9....9....6....7....9....6....5....5....7....6....6....7....5
%e A250356 ..7....6...10...10....7...10...10....7....8....9....9....7....8...10...10....7
%K A250356 nonn
%O A250356 1,1
%A A250356 _R. H. Hardin_, Nov 19 2014