A204680 Number of nX3 0..3 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..3 introduced in row major order.

4, 159, 6451, 287379, 12711292, 563046972, 24932875448, 1104148318540, 48896363697435, 2165344586789384, 95890854634053213, 4246463765107286355, 188051863862618823831, 8327753561924846574597, 368789108809170527549222

Offset: 1

Author

R. H. Hardin Jan 18 2012

Keywords

• nonn

Comments

Column 3 of A204685

Examples

			Some solutions for n=5
..0..1..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1
..0..0..1....2..1..2....0..1..0....0..0..1....0..0..1....2..3..1....2..2..1
..2..0..2....2..3..0....2..3..3....1..2..2....1..2..2....1..1..3....0..3..2
..2..1..1....1..3..2....0..1..0....3..2..2....0..1..3....3..3..1....2..0..2
..3..1..0....1..1..2....1..2..1....3..3..1....1..3..3....0..1..1....3..3..1
		

Links

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

Formula

Empirical: a(n) = 33*a(n-1) +576*a(n-2) -2576*a(n-3) -38824*a(n-4) +127580*a(n-5) +909748*a(n-6) -3116838*a(n-7) -7687952*a(n-8) [phone]*a(n-9) -63026296*a(n-10) -432695012*a(n-11) [phone]*a(n-12) -5107909211*a(n-13) [phone]*a(n-14) [phone]*a(n-15) -61214998652*a(n-16) [phone]*a(n-17) [phone]*a(n-18) -101087636628*a(n-19) [phone]*a(n-20) [phone]*a(n-21) -85493406672*a(n-22) [phone]*a(n-23) [phone]*a(n-24) -38953846080*a(n-25) [phone]*a(n-26) [phone]*a(n-27) -6291032832*a(n-28) [phone]*a(n-29) [phone]*a(n-30) for n>33