A239859 Number of 2 X n 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.

2, 3, 9, 12, 29, 63, 100, 215, 468, 785, 1654, 3515, 6048, 12676, 26381, 46460, 96810, 198286, 355994, 737992, 1493159, 2724777, 5619409, 11263131, 20836948, 42752798, 85081916, 159218104, 325067366, 643478067, 1215731399, 2470549558, 4871466920

Offset: 1

Author

R. H. Hardin, Mar 28 2014

Keywords

• nonn

Comments

Row 2 of A239858.

Examples

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

Links

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

Crossrefs

Cf. A239858.

Formula

Empirical: a(n) = a(n-1) +a(n-2) +7*a(n-3) -8*a(n-4) -7*a(n-5) +9*a(n-7) +10*a(n-8) -24*a(n-9) +5*a(n-10) +29*a(n-11) -18*a(n-12) -10*a(n-13) -10*a(n-14) +16*a(n-15) +12*a(n-16) -12*a(n-17) for n>21.