A250347 Number of length n arrays x(i), i=1..n with x(i) in i..i+4 and no value appearing more than 2 times.

5, 25, 122, 581, 2724, 12734, 59406, 276816, 1289208, 6002949, 27948445, 130114896, 605739129, 2819935996, 13127753699, 61113960653, 284504996836, 1324460800690, 6165782447251, 28703656674418, 133624541803551, 622064214270768

Offset: 1

Author

R. H. Hardin, Nov 19 2014

Keywords

• nonn

Comments

Column 4 of A250351

Examples

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

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -4*a(n-3) -9*a(n-4) -36*a(n-5) +7*a(n-6) +23*a(n-7) +13*a(n-8) +2*a(n-9) -5*a(n-10) +a(n-12)