A228217 Number of second differences of arrays of length n+2 of numbers in 0..7.

29, 519, 7309, 88215, 951049, 9399615, 86929081, 766106895, 6537612649, 54701587935, 452558355481, 3719467815855, 30436607366089, 248242046141055, 2019169299698041, 16385984911571535, 132716292890482729

Offset: 1

Author

R. H. Hardin Aug 16 2013

Keywords

• nonn

Comments

Column 7 of A228218

Examples

			Some solutions for n=4
.-8....0...-8....1....4..-11....3....7..-10...-1...-4....4...-2....8...-3...-9
.13...-2...-1....5...-3....7....0...-4....3...10....8...-2...-8...-4....5...11
-12...-3....4...-7...-4...-3...-5....8...-1..-13....0...-3....7...-8....3...-1
..8....9....2....4....1....3...-2..-11....6...12..-10...-3....7...11...-3...-4
		

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -56*a(n-2) for n>15