A250365 Number of length 7 arrays x(i), i=1..7 with x(i) in i..i+n and no value appearing more than 3 times.

128, 2187, 16128, 76300, 272760, 803382, 2052904, 4698744, 9854280, 19251970, 35471832, 62220324, 104664664, 169827630, 267047880, 408510832, 609855144, 890859834, 1276217080, 1796395740, 2488600632, 3397832614, 4578054504

Offset: 1

Author

R. H. Hardin, Nov 19 2014

Keywords

• nonn

Comments

Row 7 of A250361

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = n^7 + 7*n^6 + 21*n^5 + 147*n^3 + 49*n^2 + 7*n for n>4