A203652 1/25 the number of (n+1)X5 0..4 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements.

6561, 519445, 44577561, 3906948333, 343812029649, 30292030417413, 2669260624372937, 235230466316286557, 20729666228601067777, 1826821038860074533877, 160989718241260912957305

Offset: 1

Author

R. H. Hardin Jan 04 2012

Keywords

• nonn

Comments

Column 4 of A203656

Examples

			Some solutions for n=4
..0..2..2..0..0....4..1..0..1..1....0..3..2..3..4....1..2..4..4..4
..4..0..2..2..0....0..4..1..3..1....4..0..3..3..3....4..1..2..4..2
..3..4..0..2..2....0..0..4..1..3....2..4..0..3..1....1..3..1..2..0
..0..3..4..0..2....2..0..0..4..1....3..2..4..0..3....3..3..3..1..2
..3..0..3..4..0....3..2..0..0..4....4..3..2..4..0....2..3..1..3..1
		

Links

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

Formula

Empirical: a(n) = 69*a(n-1) +2528*a(n-2) -75120*a(n-3) +59456*a(n-4) +1531904*a(n-5) -345088*a(n-6) -1646592*a(n-7)