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

128, 1791, 12620, 59406, 214716, 644040, 1681860, 3932472, 8409252, 16713576, 31259100, 55546440, 94493292, 154825032, 245530836, 378390360, 568576020, 835335912, 1202762412, 1700651496, 2365457820, 3241350600, 4381375332

Offset

1,1

Comments

Row 7 of A250351

Links

R. H. Hardin, Table of n, a(n) for n = 1..91

Formula

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

Example

Some solutions for n=4
..1....1....2....2....2....1....1....0....0....2....4....3....1....0....1....3
..3....3....1....1....3....2....4....1....4....1....2....2....3....5....4....2
..2....2....2....5....4....3....6....6....4....4....2....4....5....2....6....6
..3....4....6....7....7....7....7....5....6....6....7....6....5....3....6....4
..6....4....4....5....4....6....6....6....5....6....4....5....6....7....5....5
..5....9....6....9....9....6....7....9....6....5....5....7....6....6....7....5
..7....6...10...10....7...10...10....7....8....9....9....7....8...10...10....7

Crossrefs

Sequence in context: A332545 A269081 A200789 * A269587 A232053 A250234

Adjacent sequences: A250353 A250354 A250355 * A250357 A250358 A250359

Keyword

nonn

Author

R. H. Hardin, Nov 19 2014

Status

approved