A240272 Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.

3, 7, 35, 157, 713, 3263, 14895, 68101, 311509, 1424689, 6516312, 29807450, 136351053, 623728103, 2853225545, 13052077767, 59706884718, 273130241113, 1249440509707, 5715597380517, 26146153523610, 119606300969406

Offset: 1

Author

R. H. Hardin, Apr 03 2014

Keywords

• nonn

Comments

Row 2 of A240271

Examples

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

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -20*a(n-2) +34*a(n-3) -84*a(n-4) +92*a(n-5) -68*a(n-6) +222*a(n-7) +13*a(n-8) -251*a(n-9) +25*a(n-10) -495*a(n-11) +485*a(n-12) -44*a(n-13) -180*a(n-14) +554*a(n-15) -648*a(n-16) +14*a(n-17) +152*a(n-18) -190*a(n-19) -140*a(n-20) +397*a(n-21) -273*a(n-22) +75*a(n-23) +167*a(n-24) -136*a(n-25) +27*a(n-26) for n>28