A232338 Number of 4Xn 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally, with no adjacent elements equal.

1, 42, 308, 734, 4906, 13170, 82526, 239992, 1398710, 4333362, 23808020, 77703762, 406751730, 1385692672, 6971295054, 24603895150, 119805137680, 435349233940, 2063663956954, 7681867046626, 35616414149972, 135245995065394

Offset: 1

Author

R. H. Hardin, Nov 22 2013

Keywords

• nonn

Comments

Row 4 of A232335

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +15*a(n-2) -7*a(n-3) +8*a(n-4) -40*a(n-5) +8*a(n-6) -14*a(n-7) +38*a(n-8) +12*a(n-9) +3*a(n-10) -11*a(n-11) -27*a(n-12) +7*a(n-13) -6*a(n-14) +20*a(n-15) -5*a(n-16) +5*a(n-17) -7*a(n-18) +a(n-19) -a(n-20) +a(n-21) for n>24