A207742 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically.

9, 81, 387, 1849, 10535, 60025, 327075, 1782225, 9840285, 54331641, 298827711, 1643572681, 9050656627, 49839223009, 274344889595, 1510158343225, 8313840821405, 45770001214609, 251966391900979, 1387088943911449

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 4 of A207741

Examples

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

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +32*a(n-3) +132*a(n-4) -238*a(n-5) -136*a(n-6) -1068*a(n-7) -3958*a(n-8) +5414*a(n-9) +7248*a(n-10) +3912*a(n-11) +23868*a(n-12) -23346*a(n-13) -29268*a(n-14) -4140*a(n-15) -61497*a(n-16) +37350*a(n-17) +24948*a(n-18) -5400*a(n-19) +52920*a(n-20) -33264*a(n-21) -2592*a(n-22) -11664*a(n-24) +7776*a(n-25)