A245162 Number of length n 0..7 arrays with new values introduced in order from both ends.

1, 1, 2, 4, 9, 23, 65, 199, 654, 2296, 8569, 33825, 140581, 612933, 2795182, 13298464, 65852872, 338694406, 1805809431, 9963758843, 56805378239, 334156440067, 2025424520548, 12633195093794, 80976535864874, 532652296499548

Offset: 1

Author

R. H. Hardin, Jul 12 2014

Keywords

• nonn

Comments

Column 7 of A245163

Examples

			Some solutions for n=7
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....0....0....1....1....1....1....1....1....0....1....0....0....1....0....1
..0....0....1....1....0....1....2....2....1....1....1....1....0....0....0....1
..2....0....2....0....1....1....3....1....1....0....2....1....1....0....0....1
..0....1....1....1....1....0....2....1....1....0....1....1....1....1....0....0
..1....1....1....0....0....1....1....1....1....1....1....1....1....0....1....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
		

Links

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

Formula

Empirical: a(n) = 50*a(n-1) -1127*a(n-2) +15148*a(n-3) -135303*a(n-4) +846930*a(n-5) -3816041*a(n-6) [phone]*a(n-7) -29761816*a(n-8) [phone]*a(n-9) -59753232*a(n-10) [phone]*a(n-11) -20839680*a(n-12) +4147200*a(n-13) for n>14